A $1.1 billion upgrade of the Royal Australian Air Force's (RAAF) main operational base in northern Australia is being impacted by coronavirus travel restrictions, the Defence Force says.

Key points: Tindal RAAF Base will undergo a $1.1 billion upgrade to expand air combat capabilities

Tindal RAAF Base will undergo a $1.1 billion upgrade to expand air combat capabilities The project includes a longer runway, new fuel storage facilities and extra accommodation

The project includes a longer runway, new fuel storage facilities and extra accommodation Defence says COVID-19 travel restrictions could impact interstate contractors

In February, Prime Minister Scott Morrison announced plans for the most significant upgrade of the Tindal RAAF Base in almost 40 years.

The upgrade is part of efforts to expand Australia and the United States' air combat capabilities in the Indo-Pacific region.

The base near Katherine is being adapted to house several of the RAAF's 72 new F-35 joint strike fighter jets and is due to be completed by the end of 2027.

An extension of the runway, extra fuel storage facilities, a new passenger terminal and more than 100 residential units are among the upgrades.

The largest portion of the $1.1 billion upgrade will go towards runway extensions and fuel storage at Tindal RAAF Base. ( Defence: OFFCDT David Campbell )

Defence director general of capital facilities and infrastructure Brigadier Matt Galton responded to questions during a federal parliamentary inquiry on Tuesday about whether the project's rollout could be delayed by the COVID-19 outbreak.

"The current COVID-19 pandemic has and may continue to impact this initial program," Brigadier Galton said.

People entering the Northern Territory are currently required to undergo 14 days of mandatory hotel isolation at their own expense, unless they are granted an exemption.

While some of the construction work at Tindal will be undertaken by NT-based companies, Brigadier Galton said interstate firms were also likely to receive contracts.

"What we are yet to test is their ability to move from whichever state they're in into the Northern Territory [to] see if there's any need for them to be quarantined for any period of time or not," he said.

"We just don't quite have certainty on that yet."

Australian Industry and Defence Network NT's Kerryn Smith said businesses were hoping for more local Defence contracts. ( ABC: Alan Dowler )

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No 'significant' impacts on seven-year project

Despite the lack of clarity, Brigadier Galton told the Standing Committee on Public Works he did not foresee any "significant" impacts on the future of the seven-year project.

"Defence and its managing contractor continue to investigate all opportunities to sustain momentum of the project, including the reprioritisation of initial works packages, opportunity to work within travel restrictions and the delivery of innovative solutions," he said.

"This will be a challenge for the team, but I am confident [it's] one that we can manage."

Australian Industry and Defence Network NT chief executive Kerryn Smith said the travel restrictions showed the importance of using NT-based contractors for the Tindal upgrades.

"It's put the spotlight back on tapping into local suppliers," Ms Smith said.

Previous Defence contracts at Tindal have resulted in more than 60 per cent of the work being allocated to NT-based contractors and Ms Smith said she hoped even more would benefit from upcoming projects at the base.

"In the current environment, where we do have restrictions on travel, this is a great opportunity for our local suppliers to now tap into this work and put their hand up and be noticed," she said.

Other aircraft that will utilise the Tindal upgrades include air-to-air refuellers such as KC-30A Multi Role Tankers and unmanned aerial vehicles like the MQ-4C Triton.

The expansion will also support US plans to ramp up its use of Tindal as part of its Force Posture Initiative.

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If you can't contact or get to your GP, but you have the symptoms, you should call 1800 008 002 This is a dedicated NT-wide coronavirus (COVID-19) number for people who need to arrange testing only

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