LH-06106 Location: Capital city locations in ACT, VIC, NSW, QLD or SA Working Arrangement: Hybrid (initial 6 weeks full‑time onsite, then minimum 3 days per week onsite) Security Clearance: Must have Negative Vetting Level 1 (NV1) About the Role Services Australia is seeking an experienced Senior Application Systems Engineer to support, administer, and enhance a range of commercial-off-the-shelf (COTS) and bespoke ICT solutions . The role supports business‑critical digital services and applications built primarily on the Microsoft .NET technology stack , operating within a complex, highly regulated government environment. The successful candidate will play a key role in ensuring the stability, security, availability, and performance of applications across web, desktop, web services, and batch processing platforms. Requirements Key Responsibilities The Senior Application Systems Engineer will be responsible for some or all of the following duties: Application Support & Administration Provide ongoing technical support and administration for corporate web and desktop applications Support .NET‑based applications , including IIS-hosted services, Windows services, web services/APIs, and scheduled batch jobs Maintain and administer application environments across development, test, and production Incident & Problem Management Diagnose and resolve complex system and application issues Participate in incident response, investigation, and root cause analysis Contribute to the resolution of problems to improve system stability and reliability Patching, Maintenance & Enhancements Plan, test, and execute application and infrastructure patching activities Ensure systems comply with security, risk, and regulatory requirements Support the delivery of minor system enhancements and operational improvements Infrastructure & Environment Management Work collaboratively with infrastructure, networking, and security teams Support physical, virtualised, and hybrid infrastructure environments underpinning application services Assist with lifecycle activities, including upgrades and retirement of legacy components Documentation & Operational Readiness Develop, maintain, and review: Technical documentation Standard Operating Procedures (SOPs) Support and operational runbooks Ensure documentation supports audit, compliance, and knowledge transfer requirements Required Skills and Experience Extensive experience supporting enterprise applications built on the Microsoft .NET technology stack Strong experience in: Windows Server environments IIS application hosting Web services and batch processing Demonstrated experience in incident, problem, and change management Proven ability to operate in high‑availability, security‑conscious environments Strong analytical and troubleshooting skills Excellent written and verbal communication skills Desirable Experience Experience within Australian Government or other large, regulated environments Familiarity with government security policies and compliance frameworks