Government backbencher Kevin Andrews has made a thinly veiled swipe at Malcolm Turnbull's prime ministership, saying he thinks voters are unhappy about "inadequate leadership" in Canberra.
Mr Andrews, an outspoken ally of former prime minister Tony Abbott, said while he was not advocating for a change of leader, Australians wanted "clear, decisive, stable leadership".
When asked if he had confidence in Mr Turnbull, Mr Andrews told Sky News: "There is a deep frustration in the community about what people see as inadequate leadership at the present time".
The Victorian MP directly linked this frustration to the uncertainty about MPs' citizenship that has engulfed Parliament in recent months.
Mr Andrews, a former Howard and Abbott minister, pointedly said that former prime ministers such as Bob Hawke and John Howard had even temperaments, listened to voters and colleagues and were able to argue a case.
This follows comments from Mr Andrews earlier in the week, in which he described Mr Turnbull as leader "at the moment".
Also on Sunday, Finance Minister Mathias Cormann dismissed suggestions Mr Turnbull could be replaced by deputy Liberal leader Julie Bishop.
"Yes, of course I'm confident that Malcolm Turnbull will lead us to the next election, he's providing very strong, effective leadership to our team," he told Sky News.
"Beyond that, I'm not going to get myself involved in gossip."
The Coalition has long been suffering in opinion polls under Mr Turnbull. According to the most recent Newspoll, released last Monday, the Coalition trails Labor, 46 to 54 per cent. This was 22nd Newspoll in a row that had the government in an election-losing position.
Citizenship questions: 'Unsustainable to do nothing'
Since he was demoted from cabinet by Mr Turnbull in 2015, Mr Andrews has been an outspoken member of the backbench. Recently this has included breaking ranks on a proposed audit of MPs' citizenship, which the Coalition has been resisting.
On Sunday, Mr Andrews renewed his calls for action, saying the government was not able to get any clear air because of continued questions about MPs' citizenship status.
"It's unsustainable to do nothing," Mr Andrews said. "The issue is out there and running and it's not going to go away until its resolved."
Mr Andrews' comments came as another Turnbull government MP - junior minister Alex Hawke - faced questions about his citizenship status after it was noted his mother was born in Greece.
The assistant immigration minister has rejected claims he could be a dual citizen by descent, saying he was born in Wollongong and has never "held or acquired or sought Greek or any other citizenship".
"I am an Australian citizen only," he told News Corp.
A person acquires Greek citizenship at birth "if said person is born to a parent of Greek nationality" - and it is not required to be activated. But Greek citizens do need to be officially registered.
Cabinet minister Kelly O'Dwyer said Mr Hawke had made his status clear and people needed to take a "deep breath".
"We have rule of law in this country. We don't have a reverse onus of proof here where you're guilty until proven innocent," she told the ABC.
"If someone believes that there is a member of parliament or a Senator who is not in compliance with their obligations under the constitution, they can move a motion in the House of Representatives or in the Senate to refer them to the High Court.
"So no witch-hunt, no Salem witch trial, will actually take away from the fact that the High Court is the only arbiter on this question."
Greens leader Richard Di Natale reiterated his party's call for a "full, frank and transparent audit".
"We don't know if the government has the numbers in the Parliament to govern," he told the ABC. "We don't know if decisions being made by ministers are valid decisions."