It's tradition for the Nationals to throw open the leadership - if the party performed well at the polls, there are usually no challengers.

But Barnaby Joyce will lose a number of allies to retirement or Senate ticket relegation, including MPs Damian Drum, Ken O'Dowd and George Christensen, and NT Senator Sam McMahon.

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The Nationals have never lost a seat under Mr Joyce, who is believed to have wrestled control of the Nationals leadership off his predecessor Michael McCormack by one vote.

The Deputy Prime Minister was asked if he would still have the numbers within the party room following the election, regardless of the party's performance.

"That's a question for the party room," Mr Joyce said.

"I'll never ever preempt what other people's decision may be. I think all would agree the Nationals have done a pretty good deal and I'll stand by my record."

Mr McCormack has not ruled out another leadership tilt. Publicly, the Nationals said one of the main reasons for the leadership change was Mr Joyce's ability to negotiate hard within the Coalition party room and deliver big wins for the regions.

However, Mr McCormack said his dumping as leader came down to one thing; some members of the party voting him out in exchange for a promotion to the frontbench.

"There were many wins I had behind closed doors with Liberal leaders, [Prime Minister] Scott Morrison included, that I didn't then go and shout from the rooftops to everybody to let them know I had effected change," Mr McCormack said.

Mr Joyce has been campaigning hard with the Nationals candidates replacing his former allies, particularly in Queensland, which could pay dividends in the party room post election.

If the Nationals go backwards and lose a seat, there's a good chance Mr Joyce will face a challenge.

However, if the Nationals retain all their seats or gain a seat - the party is targeting Hunter in NSW and Lingiari in NT - his leadership should be safe.