Northern Territory senator Sam McMahon has lost her Country Liberal Party preselection battle with Alice Springs deputy mayor Jacinta Price in a blow to the Nationals.
Ms Price will now run as the top CLP candidates for the Senate at the next election after winning the preselection ballot on Saturday.
"I am deeply humbled and grateful for the support of the Country Liberal Party as well as the people of NT and Australia," she wrote on Facebook.
Senator McMahon said she respected the ballot and thanked her supporters.
But she is disappointed with "political attacks" against her this week, referring to media reports suggesting she was drunk in the Senate chamber.
The senator said she had been diagnosed with severe hypertension on Thursday with symptoms including fatigue, vertigo, and dizziness.
"I was unwell several times during the week including on Tuesday night and others have chosen to use that for political gain and to link events which should not have been linked," Senator McMahon wrote on Facebook.
"The media has allowed themselves to be manipulated."
She also said concerns raised earlier this week about a toxic culture in her office had already been dealt with.
"I find it disgraceful that a woman should be attacked by a man criticising her for allegedly being attacked by another man," Senator McMahon said.
"The logic of that escapes me and the media needs to consider the way it reports these matters."
She said she would continue on as an NT senator until the next federal election.
Senator McMahon also plans to introduce a bill which will "right a wrong and return the Territory's right to make democratic decisions" in August.
The CLP have chosen former Lingiari candidate Tina MacFarlane to run against sitting Labor MP Luke Gosling in the seat of Solomon.
The party have also chosen Ms Price's colleague Alice Springs Mayor Damien Ryan to run in the seat of Lingiari.
Ms Price's preselection is a blow to Nationals leader Barnaby Joyce, who received Senator McMahon's backing when he toppled Michael McCormack earlier this week.
Mr Joyce supported Senator McMahon's candidacy, but she was unable to secure the numbers.
Ms Price is expected to sit in the Liberals' party room in Canberra, and the loss could cut the number of Nationals in federal parliament.
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.
Mr Joyce will spend the weekend putting the final touches to his ministry line-up, 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.
Australian Associated Press