Mr McCormack spoke just after 1pm on Monday after being defeated in a leadership ballot earlier that morning.

"I have been honoured to serve the National Party as its leader for the past three years, I have been privileged and humbled to do that," Mr McCormack said.

"The National Party has been the party for regional people for more than 100 years; it will go on irrespective of who is the leader."

Mr McCormack, who at times appeared emotional during his address, said he was "just a boy from Marrar" and it was a testimony to how great Australia was that he was able to go from a village of about 100 people when he was born to such high office.

"This has been a democratic decision and I do accept it. This is the way politics is. Is it disappointing? Yes. Will I continue to serve the people of the Riverina? Of course I will," Mr McCormack said.

"I'll take some time to think about my future but it was also a humbling privilege to serve the people of the Riverina in this role as Member for Riverina."

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Mr McCormack thanked his colleagues for giving him the opportunity to lead the party since February 2018 and said it had been a "deep honour" to serve as the Minister for Infrastructure, Transport and Regional Development during that time as well.

"It have worked well with [Prime Minister] Scott Morrison to ensure we have good and stable government in such challenging times, times that no-one could have imagined: there has been drought, there has been bushfires, cyclones, storms, floods and COVID-19," he said.

Mr McCormack named the creation of the Murray-Darling Medical Schools Network as one of his greatest political achievements as Deputy PM, along with the Local Roads and Community Infrastructure Program that had delivered $2.5 billion for councils and establishing the National Water Grid.

"I'm proud that the Murray-Darling Medical Schools are busy training doctors from start to finish and that has been a big achievement as there were people who were not so much in favour of that and I made sure that it happened," Mr McCormack said.

Labor opposition leader Anthony Albanese said Mr McCormack was a decent person and the government was being "self-indulgent in the middle of a pandemic" due to the leadership contest.

"There has been no reason for the rolling of the leader of the National Party other than self-indulgence and a power-hungry mob engaging in internal politics at a time when we should be focused on that happens outside [Parliament House] not what happens inside," Mr Albanese said.

Under further questioning about his future plans as Riverina MP, Mr McCormack pointed out that he had already been pre-selected by the National Party to contest the next election.

"I owe the people of the Riverina gratitude because they have sent me to Parliament four times now and I have been very proud, It's one of the best places in the nation," he said.

"I've been pre-selected so I will weigh those options up."