CANBERRA, AAP – Barnaby Joyce faces a test of his leadership when Northern Territory Country Liberal Party members vote on a Senate candidate for the next election.

NT senator Sam McMahon backed Mr Joyce in this week’s Nationals leadership ballot in which he defeated Michael McCormack.

In turn, he is supporting her candidacy, but she faces a tough fight against Alice Springs mayor Jacinta Price in Saturday’s ballot.

However, he has had to cancel a planned flight to Darwin due to COVID-19 restrictions and will instead seek to video-conference into the CLP meeting.

If Ms Price wins preselection, and goes on to secure the Senate seat at the next election, Mr Joyce’s party room will be down one member, as she is expected to sit in the Liberal party room when in Canberra.

The proportion of its party room numbers is key to how many ministries the Nationals hold in a coalition government with the Liberals.

Numbers are already under pressure with at least one Nationals MP, Queensland’s George Christensen, retiring at the election due by May 2022.

Former Liberal candidate Warren Mundine told CLP members in a letter, seen by AAP, Ms Price is “the voice the Northern Territory needs”.

“Jacinta is bringing Aboriginal people … into the movement for common sense, pro-family, pro-business, pro-jobs and conservative values and take it up to the woke socialist left.”

Nationals colleagues came to Senator McMahon’s defence this week when media reports suggested she was drunk in the Senate chamber – which she denies, saying she has been unwell.

“I don’t put a lot of weight in anonymous claims, especially ahead of her preselection in the Northern Territory this weekend,” colleague Matt Canavan said.

NT Labor MP Luke Gosling, who sent her a get-well message, said it was a difficult and stressful time for Senator McMahon.

Also in the running when the party’s central council meets in Darwin on Saturday is CLP leader Lia Finochiaro’s former chief of staff, Tim Dixon.

Mr Joyce will spend the weekend putting the final touches to his ministry lineup, expected to be sworn in as early as Monday.

He was sworn in as deputy prime minister and minister for infrastructure, transport and regional development at a ceremony in Canberra on Tuesday.

It is widely expected former Nationals minister Bridget McKenzie, who oversaw the so-called sports rorts scheme, will return to cabinet less than 18 months after being forced to resign for breaching ministerial standards.

There is also speculation Veterans Affairs Minister Darren Chester will be demoted.

Mr Chester gave a valedictory-style answer in Question Time on Thursday as he paid tribute to veterans and their role in protecting democracy.

“Despite the shenanigans you sometimes see in this place, this chamber respects your service,” he said.