Liberal Senator Zed Seselja says the time is right to lift the cap on public service jobs.

A controversial average staffing level cap was introduced in 2015 which forced agencies to keep staff numbers at or below 2006-07 levels - the final year of the Howard government.

The Coalition said it was part of a strategy to bring the budget back into surplus.

With Treasurer Josh Frydenberg promising the budget will be “back in black” in 2019-20, Senator Seselja wants to see change regarding staff numbers.

“It's certainly something I've been arguing for internally. I think that is the appropriate time,” he told Fairfax.

“[The cap] has been there for some time so I think it's certainly something I'd like to see and if we come back into government, that that is something we do see lift. There's no doubt about that.”

The Community and Public Sector Union has campaigned hard against the cap, and Labor has committed to remove it if it wins government.

Reports say there is a much higher number of contractors and consultants now working for the government due to the cap, which is expected to come at a higher cost to taxpayers.