The Defence Department can't say exactly how many Australian jobs will be created out of the Turnbull government's plan to make the country a top 10 global arms exporters in the next decade.
The issue was canvassed during a robust exchange between Greens senator Peter Whish-Wilson and Defence Minister Marise Payne at a Senate estimates hearing on Wednesday.
The centrepiece of the government's ambitious plan is a $3.8 billion defence export facility within the export credit agency to help companies get finance to underpin sales of equipment overseas.
"How is this good bang for our buck?" Senator Whish-Wilson asked, adding he wanted evidence it was the most cost-effective way for the government to create jobs.
Department official Marc Ablong said no calculations had been carried out.
"It's up to other agencies to determine whether there are more cost-effective ways for the government to spend the government's resources," Mr Ablong said.
Senator Payne said there would be significant growth in defence industry jobs including for shipbuilders, companies involved in battlefield medical hospitals or armoured personnel vehicles.
Australia is now ranked 19th in global defence industry exports and its market is valued between $1.5 billion and $2.5 billion a year.