Losing four ministers in seven months shows the government is falling apart, the National Party leader says.
Speaking to Morning Report, Christopher Luxon said it was not fair for opposition parties to be criticised for politicising a debate on Tuesday which discussed the current situation with former justice minister Kiri Allan as it showed a wider problem.
"It's certainly a sad situation and we all wish Kiri to get all the support and help she needs for a full recovery, but the real issue here is that this is a government that is falling apart.
"It has lost four ministers in seven months."
The issue of David Parker giving up his revenue portfolio - after Prime Minister Chris Hipkins decided against a wealth tax supported by both Parker and Finance Minister Grant Robertson - also showed the party was divided, Luxon said.
"[This is a] government that is very unstable, meanwhile, Kiwis out there in New Zealand, up and down this country, one in two of us are worried about money on a daily basis.
"This is the only country in a recession in the whole of the Asia-Pacific region. You've got crime out of control, you've got an education and healthcare system falling apart, that's where the focus should be of the government, that's where a National Party government focus will be."
Despite Hipkins saying no to Parker's wealth tax, Luxon said "it was coming" if the Labour Party was in government following the election.
He said that was because the parties it could be in coalition with - the Green Party and Te Pāti Māori - both supported a wealth tax.
But Luxon called a coalition between the three parties a "three-headed monster" that would be "inherently, incredibly unstable".
A coalition between National and ACT would be better, he claimed.
"We are in a tough, tough place and as a result, we need a strong, stable government.
"While there will be disagreements and while there will be things we don't agree on, there will be a way in which we are able to get a stable government, and that's what New Zealand desperately needs right now."
Earlier this week, Hipkins said Labour could still win the election, and writing off the party was "premature".
"We are just getting started with the campaign and there's a lot more that we have to offer.
"Just watch me."
Luxon won't rule out working with Peters
Luxon said working with NZ First leader Winston Peters was something the party had not even thought about.
However, he would not rule it out - as he was quick to do with Te Pāti Māori.
"What I can tell you is we're focused on making sure we get every single party vote for National because that's actually how you change a government and it's more importantly, how you form a strong and stable government on the other side.
"It's not something we've thought about because they're not actually in Parliament and they're below 3 percent in polling so it's not a reality for us."
Luxon said his party's focus was on dealing with problems Kiwis are facing and getting the country moving forward.
"That's what we want to get on with."