Former prime minister Tony Abbott has predicted more MPs will be implicated in Parliament's ongoing citizenship fiasco, which has already eliminated six federal politicians and seen the major parties launch internal audits to weed out any others.

In the past week, Turnbull government frontbenchers Josh Frydenberg and Alex Hawke have been forced to deny they could have inadvertently acquired dual citizenship through their mothers. But Prime Minister Malcolm Turnbull has strongly resisted a Parliament-wide probe despite growing calls for a full-scale audit, including from Coalition MPs.

Mr Abbott said it was up to the Prime Minister to decide how to resolve the situation, but warned the government and country could not afford an "ongoing circus".

"Every day it's someone else. It was Josh last week, now it's Alex Hawke. It will probably be someone else tomorrow. That's why this matter does need to be resolved," he told radio station 2GB.