A major defence contractor at one of Australia's most secretive intelligence facilities is being sued by former employees, who claim they were not paid out their proper redundancy entitlements.

Key points: Six ex-employees are taking contractor Raytheon to court with claims of more than $2.6 million

Six ex-employees are taking contractor Raytheon to court with claims of more than $2.6 million A lawyer for the workers has said despite the base's secretive activities, he saw the dispute as a typical workers' rights conflict

A lawyer for the workers has said despite the base's secretive activities, he saw the dispute as a typical workers' rights conflict A union has claimed Pine Gap has been increasing the preferencing of US workers to help run the base

Six former employees of Raytheon said that when the company lost its contract to complete specialised IT work at the Joint Defence Facility Pine Gap near Alice Springs they were offered jobs with the organisation well below their level of expertise.

When they all refused to take on the new, less-skilled positions, Raytheon refused to pay out their redundancy entitlements, saying the employees had been offered other positions, which they had then declined.

The dispute was now being taken to court, with the workers claiming more than $2.6 million from Raytheon.

Joshua Blundell-Thornton, the industrial officer for the Australian Manufacturers Workers' Union who is representing the employees, said it was disappointing to see such a large organisation refuse to pay redundancy entitlements.

"It's quite frankly outrageous that a large, multinational defence contractor like Raytheon, who has lost the contract at Pine Gap through no fault of its workforce, is trying to get out of paying these workers their redundancies," he said.

"It is disappointing that a company this well-resourced is still trying to dodge their responsibilities and pay the redundancies entitled to these workers."

Raytheon and the Joint Defence Facility Pine Gap did not respond to requests for a comment.

In a statement, the Department of Defence said it would not comment on matters before the courts or between another company and its employees.

'It's all about trying to save dollars'

The spy base has been operating in Australia for more than 50 years, yet little is known about its activities.

The facility does, however, employ hundreds of workers and make up a large part of the Alice Springs economy.

Lawyer for the workers, Giri Sivaraman from Maurice Blackburn, said despite the base's secretive activities, he saw the dispute as a typical workers' rights conflict.

"These employees have the benefit of an enterprise agreement, and Raytheon has to comply with this enterprise agreement," he said.

"The enterprise agreement doesn't allow Raytheon to redeploy them to other positions, particularly inferior positions.

"Once their positions were made redundant they were retrenched, they were entitled to redundancy payment."

Mr Blundell-Thornton said it wasn't uncommon to see companies refuse to pay redundancy entitlements while "trying to save dollars".

"While we may not know the exact minutia of what they do on a day-to-day basis, the arguments we are putting forward about a worker being entitled to redundancy when their job is lost, is the same arguments we would be having, regardless of the secret nature of their work," he said.

Trend to hiring Americans

The union representing the employees said it believed the Joint Defence Facility may be preferencing the employment of Americans over Australians.

It is understood the workers who took over the positions of the six former IT employees with the new contractor are all US nationals.

"Our belief is that there seems to be a concerted effort by the people out at Pine Gap to contract back to American contractors who use American labour," Mr Blundell-Thornton said.

"It is starting to become more prevalent out there."

However, another former employee of the joint defence facility said he did not believe there was a deliberate effort to hire more US nationals for positions at the base.

Mr Blundell-Thornton said that in the past the workforce at the base had been "largely" Australian.

"Where now they seem to be going to getting more American contractors, so it is a pattern that we're starting to see," he said.

In a statement, the Department of Defence said it did not comment on staff composition or numbers of staff at different facilities.

A spokesperson from Maurice Blackburn said the two parties could enter into mediation over the matter.