Sussan Ley seeks discussions with nationals who oppose the league's breakup, including Barnaby Joyce, as part of an effort to fix the violation.

Ley seeks reconciliation with former leaders Joyce and Michael McCormack as well as the front office backup.

The move is because the nation and liberals continue to argue about the reasons for the division.

David Littleproud said Thursday that the historic league breakup was all about key policy commitments in the Australian region. He rejected his claim that the National Freedoms in the Shadow Ministry had made an objection to the Union policy.

Ley said earlier this week that the Nationals have sought to change the practice of shadow cabinet solidarity, a rule that requires front-end administrators to advocate for the party’s settlement regardless of their personal views.

But Littleproud said Thursday morning that it was only due to four policy requirements: the forced breakup power of large supermarkets to introduce nuclear power, a $2 billion regional infrastructure fund and telecommunications services guaranteed in the bush.

“I don’t think there is anything to expect,” Littprad said. "Sadly, we can't guarantee this, but we're ready. If we can guarantee it for that, then our door will be open."

National Senate leader Bridget McKenzie was asked Wednesday in ABC’s 7.30 plan if Ley was lying and stated that the National Shadow Secretary wanted to break cabinet unity, a condition for a new coalition agreement. Mackenzie said this was “not part of our consideration” and that the national requirements were limited to four policies.

But Ley's office backed off in a live interview, texting ABC, insisting that "it's incorrect to suggest that the unity of the Shadow Cabinet is not a sticky point."

Asked on ABC TV about the breakdown of cabinet unity, Littleproud said Ley's answer to the question was "satisfactory, reasonable and fair."

“This is not a debate in our party room because I believe what she sent back is reasonable.”

Littleproud said the national stance in parliamentary debates restored relationships to former opposition leader Peter Dutton in the last term of parliament.

He refused to say whether he tried to become deputy opposition leader of Ted O'Brien, a deputy liberal.

The growing quarrel comes after a letter from Mackenzie to Free Senate leader Michaelia Cash, who warned junior partners will have to consider whether to continue sitting in the Senate with liberals after Jacinta Nampijinpa Price defected.

McKenzie's letter was first published by news.com.au on Thursday. Nampijinpa Price has raised her party status as a Senate National after she moved to the Liberal Party room where she served as deputy leader earlier this month.

"Based on the outcome of negotiations between our two parties in the coming weeks, the National Senate Party will need to consider our position on the alliance with the Liberals in the Senate," Mackenzie wrote.

The two parties have officially split for the first time in a few days since the late 1980s, severely weakened in parliament, making it difficult for the Liberals to challenge Labor in the next election.

Former Prime Minister Tony Abbott joined the growing debate on Thursday, saying the two sides were unfavorable in the Sydney 2GB.

"If libs and nats go their separate ways, we will not have a strong opposition, we will have two opposition parties fighting each other like they are fighting a bad government," he said.

"This is the secret to permanent opposition, the secret to our permanent poor government."

Deputy National Leader Kevin Hogan said the split was driven by principles and acknowledged that the party could pay the price in the next election, including the loss of seats in Victoria and New South Wales due to the end of a shared vote with the liberals.

"We lost our position in the Shadow Cabinet in this regard... It's a decision that two of our senators can pay a huge price," he said.