Senator Ian Macdonald will bring a motion to the Liberal National party state conference next month to allow its members to split from the Liberal and National parties, reflecting his long-held belief that the Coalition is made up of three parties: the Liberal party, the National party and the LNP.

Senior cabinet ministers Mathias Cormann and George Brandis have played down a similar move by the LNP executive, which reportedly took intervention from the Nationals leader, Barnaby Joyce, to kill off.

A report in the Australian on Friday said the Queensland LNP executive considered a motion to assess forming a separate party room in Canberra.

The LNP operates as a single party in Queensland, although its MPs and senators are designated either Liberals or Nationals in Canberra.

The move could allow the party to demand more ministries and would require a second Coalition agreement with the Liberal party.

Although the motion was defeated, Joyce and Brandis, the attorney general and a Queensland senator, were reportedly forced to intervene to prevent it getting up.

Macdonald told Guardian Australia he had not been aware of the motion at the LNP executive but it mirrored his view that three parties make up the Coalition.

Macdonald said he would attempt to bring a motion to the LNP state conference in late August which would allow LNP members to sit as a separate, third party, or to continue to sit with the Liberal or National parties if they chose.

The Nationals have 22 members, including six MPs and two senators from the LNP.

Macdonald said the LNP was on track to win up to 28 Senate and lower house seats – the seat of Herbert is still in doubt and Senate counting has not been completed.

“Those respective strengths should be taken into account in any arrangements for a Coalition government, I’ve long said that,” he said.

“The LNP contribution to the federal Coalition government – not just in this election but the last couple of decades – has never been fully recognised in the make-up of the ministry.”

Speaking on Sky news on Friday, Cormann said: “There is no split. The LNP in Queensland is a division of the Liberal party associated with the National party.

“Individual members of the LNP choose whether to sit in the Liberal or National party room.

“We have a strong and united team. We’ve got high-quality ministers representing the Liberal and National parties out of the great state of Queensland.”

Asked whether the motion had been proposed and there were tensions over a proposed split, Cormann said: “Individuals in either the Liberal or National parties have views and ideas from time to time.

“There won’t be any split ... The arrangements continue as they have been.”

The Australian reported that Brandis and Joyce did not deny travelling to Brisbane for the meeting, but had declined to comment.

Brandis told ABC radio’s AM program on Friday that of the 42 frontbench positions, eight were held by LNP members or senators from Queensland.

“The most important development in the reshuffle the prime minister announced on Monday was the promotion of somebody from Queensland, senator Matt Canavan, from the junior ministry to the cabinet, so there are now four Queensland cabinet ministers.

“That is historically an equal high – there has never been more than four cabinet minister from Queensland.”

Brandis said people would “always wish their state to have more representatives in the cabinet”.

“But I wouldn’t over-interpret the disappointment of some that Queensland doesn’t have even more representatives in cabinet.”