At a press conference ap Iorwerth warned of a challenging financial situation and said his government was “dealing with significant financial pressures this year, especially in the NHS”.
“It would be irresponsible not to point out how little headroom there is in the Welsh budget as things currently stand, and how challenging the position is as we head into next year.”
He said his government’s ambition for Wales “will not be dimmed by financial challenges and constraints”.
His budget “will have to focus resources where they will make the biggest difference to people’s lives, rather than spreading funding thinly”.
The process had begun over the summer “of discussions with opposition parties to try to identify areas of common ground on which we can work together”.
Asked by BBC Wales whether he learned lessons from the supplementary budget exercise, ap Iorwerth said: “Have lessons been learned? Absolutely.
“We could have pulled the vote. I have a sense that it was useful in the broader picture, for everything to have been laid bare as it was during that supplementary budget vote. Everybody knows that we will have to bring that back.”
He said: “I have to dig even deeper and show through processes, which we are tightening up, to improve the way we engage with others.
“I know full well it’s not just about saying I want to be cooperative, it’s showing that I want to be cooperative.”
He said it had also been a learning experience for opposition parties.
“I know that we had a good deal on the table for Labour in that particular instance. They had every right to vote it down. But they also had to consider how it looks for them.”
The Welsh government has to pass a budget annually, usually in the winter months.
Worth £27bn, it covers funding for most public services controlled by Cardiff politicians, like the health service.
Welsh Conservative Senedd leader Darren Millar said he was “pleased to see this humility” from ap Iorwerth.
“It’s very clear that they’ve made a real mess of the supplementary budget vote before the summer recess.
“We want to see tax cuts, support for businesses and farmers, and we want to see disinvestment in things like unnecessary overseas offices and tree plating schemes in Uganda.
“If there is progress to be made it’s on issues like that. We’re prepared to have meaningful engagement with the Welsh government.”
He added: “There have been no formal talks. We have nothing scheduled in the diary.”
BBC News