Barnaby Joyce has finally announced he is quitting the Nationals Party, declaring he is “strongly considering” running for a Senate seat for One Nation in New South Wales at the next election.

But the maverick MP is not switching to One Nation immediately, despite widespread expectations and his much-publicised tete-a-tete dinner with party leader Pauline Hanson earlier this week.

Joyce announced his resignation from the Nationals in a brief speech to the House of Representatives before question time on Thursday, and elaborated to the media afterwards.

He told the House that where he sat in the chamber was the “ejection seat. It’s about as far away as you can get from the despatch box. And if you’re sitting here, they want you out there.”

He said in the past he had been asked to leave twice by former opposition leader Peter Dutton. He also again made clear his resentment about how he had been treated by Nationals Leader David Littleproud.

He said apart from a 90-second conversation with Littleproud - after he announced several weeks ago that he wouldn’t recontest his New England seat and would not attend partyroom meetings - he had had no communication with the leader or deputy leader of the Nationals.

“So that’s disappointing. So after 30 years with the National Party, I am resigning from the party. And that leaves me with a heavy heart. And I apologise for all of the hurt that that will cause. I really do.”

Joyce has had a mixture of entreaties to stay and criticism from Nationals colleagues in recent weeks, amid the speculation about his future move to One Nation.

Joyce started his parliamentary career in the Senate in 2005 after winning a Queensland Senate seat at the 2004 election. He made it clear on Thursday that he would like to enjoy the potential power that being a crossbench senator could bring.

“It’s the appeal also of the Senate, of just review[ing] and amend[ing] legislation. […]You’d have to come to me on each piece of legislation and say ‘what are your views?’ I’ve done the Senate before – eight years, seven months and a day. I know that I know the job.”

In a tumultuous career in the Nationals, Joyce led the party twice, and served twice as deputy prime minister.