Australia’s telecommunications sector sits at the crossroads of national security, digital trust, and everyday connectivity. As networks expand, regulations tighten, and adversaries grow more sophisticated, the role of security leadership inside telcos has never been more visible or more consequential.
What’s also changed is the shape of that leadership. While some organisations still operate with a traditional CISO title, others rely on heads of cyber, security operations leaders, or technology executives carrying security accountability across complex environments. Titles may differ, but the responsibility is the same: protecting critical infrastructure while enabling growth, resilience, and innovation.
Below are CISOs and senior security leaders shaping Australia’s telecom security landscape, from the country’s largest carriers to challengers and infrastructure providers. Some hold the title today, some have moved on to new roles, but all continue to influence how telecom security is done.
Narelle Devine — Global Chief Information Security Officer, Telstra
Few careers span military service, government, and corporate security at national scale. Narelle Devine began her journey in the Royal Australian Navy, where she ran communications and networks in high-stakes environments. That foundation carried her into government, serving as CISO for the Department of Human Services, protecting systems underpinning essential welfare and health payments.
In 2020, she joined Telstra and now serves as Global CISO, overseeing security for Australia’s largest telco across the Asia-Pacific region. Beyond cyber operations, Devine is a vocal advocate for workforce development, diversity, and rethinking traditional education pathways, bringing a people-first lens to protecting critical infrastructure.
Pieter van der Merwe — Chief Security and Risk Officer, Optus
Pieter van der Merwe brings deep experience advising technology-dependent organisations on complex security and risk challenges. Appointed Chief Security and Risk Officer at Optus in late 2025, he stepped into the role at a pivotal moment, as the telco continues to strengthen resilience, governance, and trust.
His remit extends beyond cyber alone, reflecting a broader convergence of operational risk, security, and executive accountability, an increasingly common model in large telecom organisations.
Suthagar Seevaratnam — Chief Information Security Officer, Vocus Group
A values-driven national security leader, Suthagar Seevaratnam is widely respected for bridging public- and private-sector cyber leadership. His career includes senior roles at the Australian Signals Directorate, CISO positions at the Australian National University and the Bureau of Meteorology, and now leadership at Vocus Group, a major critical infrastructure provider.
Known for ethical clarity and composure in high-risk environments, Seevaratnam blends strategic governance with deep operational expertise. He also serves as an Honorary Professor of Cyber Security Practice at ANU, shaping the next generation of cyber leaders alongside securing Australia’s digital backbone.
Robert Turney — Chief Information Security Officer, auDA
As CISO of auDA, Robert Turney is responsible for securing Australia’s .au domain—an often overlooked but foundational component of national digital infrastructure. With nearly three decades in information security, he is known for pragmatic, business-aligned security strategies that deliver real outcomes.
Turney’s leadership spans cyber programs, stakeholder engagement, and building resilient teams, reinforcing the idea that internet governance and telecom security are inseparable in today’s threat landscape.
Dian Erliasari — Senior Information Security Manager, Telstra
With nearly 20 years in cybersecurity, Dian Erliasari represents the depth of leadership within Australia’s largest telco beyond the CISO title. She is recognised for delivering security across complex environments, shaping governance, and strengthening operational readiness at scale.
A passionate advocate for diversity and mentorship, Erliasari is also a visible voice in the Australian cyber community. Her leadership extends beyond Telstra through industry speaking, community engagement, and developing the next generation of security professionals.
Matt Siomos — Cyber Security Operations Manager, Aussie Broadband
As Aussie Broadband continues to grow as a challenger ISP, Matt Siomos leads the security operations that protect its customers and networks. His role highlights how security leadership in telecom increasingly lives within operations, where detection, response, and resilience meet customer experience.
Siomos represents the new wave of security leaders ensuring that fast-growing providers don’t outpace their security foundations.
Sachit Nagpal — Cyber Security Manager, Vodafone Australia
Sachit Nagpal leads large parts of Vodafone Australia’s cybersecurity landscape, covering SOC operations, identity and access management, network security, and endpoint protection. Working within the Vodafone/TPG environment, his role underscores the complexity of securing merged telecom ecosystems.
His leadership spans both strategy and delivery, ensuring security programs scale alongside business and network transformation.
Lee Barney — Former Chief Information Security Officer, TPG Telecom
While no longer in the role, Lee Barney’s impact at TPG Telecom continues to resonate across the sector. As CISO, he led a large-scale post-merger security transformation, unified operations across multiple brands, built a national Cyber Security Centre of Excellence, and uplifted compliance under the SOCI Act.
Known for aligning cyber risk with business outcomes and driving cultural change, Barney remains an influential voice in critical infrastructure security.
James Fields — Head of IT & Security, Superloop
James Fields brings two decades of cybersecurity experience to Superloop, where he oversees IT and security for a fast-growing connectivity provider. His career evolution from infrastructure to global cyber leadership gives him a practical lens on balancing resilience with operational efficiency.
Fields is known for building security programs from the ground up, including SOC design, strategy execution, and board-level engagement.
Tosin Foloruns — Manager, Information Security, BAI Communications
At BAI Communications, Tosin Foloruns leads information security across a business operating critical communications infrastructure globally. With experience managing ISO 27001 certifications across multiple continents, his work focuses on compliance, risk, and securely enabling business outcomes.
His role reflects the global nature of telecom security and the importance of standards-driven leadership.
Melissa Lumley — Head of Technology and Security, BAI Communications
Melissa Lumley brings more than 20 years of technology leadership to BAI Communications, combining cybersecurity, IT operations, and people-centric leadership. Her work spans digital transformation, security frameworks, and building resilient technology ecosystems.
As a senior leader carrying both technology and security accountability, Lumley exemplifies the convergence shaping modern telecom leadership.
Andrew J. — Head of Cyber Security, Swoop
At Swoop, Andrew leads cybersecurity for a growing connectivity provider, ensuring security scales alongside expansion. His role highlights how security leadership is becoming integral even in smaller, fast-moving telecom organisations.
Why These Leaders Matter
Australian telecom security is no longer defined by a single title or function. It’s shaped by leaders who understand networks, regulation, people, and risk, and who can operate at the intersection of national infrastructure and commercial reality.
Whether they hold the CISO title today, have moved on to new challenges, or lead security from adjacent roles, these individuals are setting the tone for how Australia protects the systems that keep the country connected.