Sussan Ley's office says Bridget McKenzie made false claims about cabinet solidarity

Opposition Leader Sussan Ley's office has accused National Party senator Bridget McKenzie of making false claims about her party's reason for leaving the Coalition.

Senator McKenzie told 7.30 on Wednesday night that the Coalition split occurred because the opposition leader could not give the Nationals the guarantees they sought on four key policies.

Asked whether the issue of shadow cabinet solidarity was also a key issue in the negotiations, as the Liberal leader asserted, Senator McKenzie said: "It was solely on those four policies."

"I can tell you, because I was in the National party room that made this decision, the decision that was then conveyed to the Liberal leader. And that was not part of our consideration … it was solely on those four policies," she said.

Pressed on whether Ms Ley had misrepresented the discussions, Senator McKenzie said: "Sussan Ley was not part of our partyroom discussions. I was … I can categorically tell you why we made the decision we did and what that was based on."

The four policies, according to earlier statements from National Party leader David Littleproud, were: nuclear energy, a regional Australia future fund, supermarket divestiture and regional telephone service obligations.

During the program, Ms Ley's office sent a text to 7.30 host Sarah Ferguson disputing Senator McKenzie's denials.

The text said: "It is not correct to suggest shadow cabinet solidarity was not a sticking point. We have it in writing that it was a requirement from their leader's office to ours."

Ms Ley's office texted a second time, adding about Senator McKenzie: "Her language was deliberate to make it sound like it was just about the policies. That is just not correct."

Senator McKenzie later told 7.30 she stood by her comments on the program and said the claims made by Ms Ley's office did not reflect the discussion in the Nationals party room.

"The claims made above were not the basis of the Nationals partyroom decision not to form a Coalition at this time," she said in a statement.

Mr Littleproud has been contacted for comment.

The Coalition split came on Tuesday after days of negotiations between the two sides failed to result in a coalition agreement, breaking with a longstanding tradition.

Mr Littleproud made the announcement at Parliament House, describing it as one of the "hardest political decisions of his life".

He told reporters the Nationals would continue to work constructively with the Liberal Party but they would not re-enter a formal coalition agreement at this stage.

"The National Party will sit alone on a principle basis," Mr Littleproud said.

"On the basis of looking forward, not having to look back, and to try and actually regain important policy pieces that change the lives of the people we represent."

Since then, the leaders of both parties have repeatedly said they will leave the door open for a reunion before the next election, with Ms Ley describing herself as a "committed Coalitionist".

Mr Littleproud said on Tuesday he was hopeful the two parties would be able to come to a new agreement before the next federal election in three years, but added that his party would contest the election alone if that did not happen.

After Wednesday night's incident, the parties now seem further apart.

Watch 7.30, Mondays to Thursdays 7:30pm on ABC iview and ABC TV