Malcolm Turnbull faces further possible defections and a ministry reshuffle after Ian Macfarlane's switch to the Nationals.
The dumped former Liberal minister announced his intention to join the rural party on Thursday after the Nationals discussed his addition in an hour long meeting.
He emphasised his three decades representing rural Australia, saying his depth of experience was second only to Nationals leader Warren Truss.
"I'm as National party as anyone," Mr Macfarlane told reporters in Canberra.
Other MPs, including fellow Queenslander Scott Buchholz, who lost his position as chief whip in the reshuffle, are believed to be considering a similar move.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Mr Buchholz, who would not comment on the speculation, tweeted a picture of himself meeting Nationals MP Michael McCormack discussing regional issues soon after Mr Macfarlane's announcement.
"Making a eleventh hour bid for local Stronger Regions projects last day of Parl sittings," he said.
Mr Truss said he'd had no discussions with Mr Buchholz on the issue but others who sat in the Liberal party room would be welcome to join.
The Nationals are likely to use the addition of a 22nd member to push for another frontbench seat.
Mr Truss said larger numbers in the party room would trigger an entitlement in the coalition agreement to increased representation on the frontbench.
"Naturally we would expect those elements of the agreement to be honoured," he said.
But no commitment had been given to Mr Macfarlane that he would take a leadership role in the party.
Nationals who'd been there longer would "obviously start with a bit of an advantage", he said.
Mr Macfarlane, who was relegated to the backbench when Mr Turnbull took office, said he would push for a future ministerial post on the basis of merit.
The former industry minister said he was "very disappointed" in missing a ministerial spot in the September reshuffle.
But he dismissed any rift with Mr Turnbull, saying the alternative to switching was to leave parliament.
"If the opportunity comes in the National party to serve again in his ministry I would relish it."
Mr Macfarlane will need permission from the Liberal National Party federal district council in his electorate of Groom to make the shift.
