Coalition back together for second time in eight months to defeat 'awful' government

"The Coalition are back in coalition, in the national interest, to hold this awful Albanese government to account," Opposition Leader Sussan Ley said in a joint announcement with Nationals leader David Littleproud on Sunday.

"We have a task to chart the course back to [being in] government," she said, calling the partnership the most successful one in Australian government history.

Ms Ley and her Nationals counterpart were insistent there would not be another split, despite two in eight months.

"This wasn't about personalities. This was about principles," Mr Littleproud said.

He told reporters the split happened because the Coalition was not given enough time to rigorously debate hate speech laws that passed last month, despite saying previously he could not be in a Coalition where Ms Ley was leader.

"I think that says to the Australian people that you've got a Coalition that cares," he said.

The Coalition will introduce a decisions register and codification that neither individual party is able to overturn decisions of the shadow cabinet. All shadow ministers will sign a solidarity agreement.

Ms Ley originally called for a six-month suspension from the shadow cabinet for three Nationals senators who crossed the floor to vote away from the Liberals on the government's hate speech bill.

Doing so broke a convention of shadow cabinet solidarity, despite the trio following the Nationals party room position. Usual convention for shadow cabinet members who break solidarity is to resign.

When Ms Ley accepted the senators' offers to step down, Nationals leader David Littleproud pulled the pin on the Coalition.

The messy three-week breakup that ensued ended Sunday afternoon, following breakthrough talks between Ms Ley and Mr Littleproud on Saturday.

The Nationals sat on the crossbench last week, the first ordinary sitting week of the year, as Ms Ley's frontbench in both houses looked notably thin.

But the leaders have now agreed to a shorter suspension period for the three senators, ending March 1, which will see the Coalition ranks once again filled.

The Nationals, who all left the frontbench in solidarity with the three senators, will all return to the shadow cabinet at the start of next month.

Mr Littleproud and deputy leader Kevin Hogan will resume attending shadow cabinet meetings immediately, as leaders.

The Nationals will retain their committee positions, which, before the breakthrough negotiations, were expected to be axed by the Liberals.

"You need to be inside the room with policies that can actually be implemented. That's what the Coalition has proven for 100 years. But we need to make sure the foundation stones are respect, trust and integrity," Mr Littleproud told media on Sunday morning.

He did not comment at the time on details of his conversations with Ms Ley.

The Coalition was expected late last week to be beyond repair and Ms Ley's position appeared to be at risk, with Liberal frontbencher Angus Taylor expected to mount a leadership challenge off the back of the split.

Despite their reunification, the two parties will need to deal with structural issues, including an expected shift to the right from the Nationals in an attempt to shield their voter base from One Nation votes. It is the second time the Coalition has split in less than a year.