Labour had last held Northland (then the Bay of Islands electorate) in 1938.
"We have to demonstrate to Kiwis that we'll oppose the Government strongly and we'll criticise
but also be constructive doing so. And we have to propose new ideas," Luxon said.
"I think people are starting to get a sense that's the mode we're working in. If we do that job right, they'll start to see us as an alternative government in waiting that has the ideas and the plans and can build back the trust so that they elect us in 2023.
"Dr Shane Reti is very senior in the National line-up, he's a man of great integrity, mana, he cares deeply about the healthcare profession and what's happening in healthcare in general. He's going to make an outstanding Minister of Health.
"So I think we've got the talent and the people that have actually got the lived experience that are passionate about the areas and the portfolios they are responsible for. They will oppose the Government strongly but importantly propose ideas over the coming 12 months.
"That's really what I've asked the team to do, so they are clear that when they become new ministers in our government they are ready to go from day one."