Simon Bridges has admitted the National Party made mistakes on housing while they were in Government.
In an interview with Q+A, he was asked if his party had "modernised" their stance on housing.
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"Yeah, I don't think we got all of that perfect," he replied.
"I think there are things we need to do. I think we've got two things to do; hold the Government to account on a lot of uncertainty, increased costs on households, these law and order things we're talking about, but it's also incumbent on us to develop really exciting, positive plans for 2020.
"And if we don't do that, we don't deserve to be the Government."
Under the previous National Government, the number of state houses in New Zealand fell from 67,000 to about 63,000, and the waiting list for a state house almost doubled between 2007 and 2017.
One of Labour's 2017 campaign promises was 100,000 affordable homes within 10 years, compared to National's 26,000 - of which only some would be affordable.
Mr Bridges, who recently announced that his party would give the Government bipartisan support on climate change, said National had changed for the better under his leadership.
"It's not going to be a re-election of the one that lost," he said of the 2020 general election.
"Our values are the same. If you talk to John Key or Bill English or myself, our values are there. But I do want to modernise it.
"I think you've seen that on this environmental stance that we've been talking about today, there's a stamp on my leadership."