Federal Paterson MP Meryl Swanson, state Port Stephens MP Kate Washington and Newcastle mayor Nuatali Nelmes were among those who signed a letter urging Qantas, Jetstar's owner, to retain the Newcastle maintenance and crew base operations.

Jetstar announced last month it was closing the facilities, which will result in the loss of 179 jobs.

The letter to Mr Joyce highlights that the Lower Hunter is the second fastest growing area in NSW.

"Newcastle Airport is growing rapidly and already accommodates a seasonal international flight to New Zealand. We are currently working with the federal government and Defence in the hope of upgrading the runway, which will allow wide-bodied aircraft to have a frequent landing and take-off schedule out of Newcastle," the letter says.

It is feared the loss of the jobs, which include 112 engineering staff, 23 pilots and 44 cabin crew, could also jeopardise the runway extension case as well as the recently announced Special Activation Precinct.

Transport Workers' Union state secretary Richard Olsen accused Jetstar of abandoning its Newcastle-based cabin crew.

"Families have had their lives destroyed by this announcement," Mr Olsen said.

"Today we ask Jetstar the question, why abandon regional jobs? Jetstar is not committed to maintaining fulltime jobs closer to home for these workers."

Jetstar, which has offered to let some workers relocate to Melbourne or Brisbane, said it was seeking to consult with unions about the changes.

Newcastle Lord Mayor Nuatali Nelmes said she stood in solidarity with the Jetstar workers.

"There is never an acceptable time to cut jobs in this manner and COVID-19 is absolutely no excuse to move these valuable, skilled jobs away from Newcastle," she said.

"The aviation industry will recover from the uncertainty of the global pandemic, and these jobs will be absolutely crucial to ensuring the ongoing safety of workers, and customers flying with Jetstar."

A Jetstar spokeswoman said an allegation that planes previously maintained in Newcastle were now being sent to Singapore was "absolutely incorrect."

Jetstar chief executive Gareth Evans said earlier on Thursday that closing the Newcastle facility was a difficult decision.

"As an airline Jetstar is very different from the one it was 16 years ago and the Newcastle base is no longer fit for purpose in terms of size or geography."