National's tax cuts stance means it can't be trusted on abortion - Michael Wood

National and Labour are continuing to go tit-for-tat over tax after the Opposition accused the Government of playing "dirty political games".

Opposition leader Christopher Luxon has this week come under fire for his party's stance on tax cut promises amid reports his National Party had dumped its policy of adjusting tax thresholds to inflation. 

National Finance spokesperson and deputy leader Nicola Willis later confirmed its promise to index tax thresholds to inflation remained and the party was committed to tax reduction. 

Labour's Michael Wood, speaking to AM on Friday, said the Opposition can't be trusted.

"If you can't trust them to keep a straight position on this, how can you trust them on issues like abortion and other issues?" Wood asked, seemingly referring to National coming under fire in June when one of its MPs praised the overturning of abortion rights legislation in the US. 

Asked whether National had backtracked on its tax policy, MP Erica Stanford said the party had been "absolutely clear".

"What [Willis] was saying was that there will be a suit of things in our tax policy, but the core tenant of our tax policy - which is indexing tax brackets for inflation - has not changed," said Stanford, appearing on AM alongside Wood.

She also accused Labour of liking "to play games".

But Wood hit back, saying National lacked experience. Wood claimed the Opposition wasn't "being clear about what you deliver and sticking to that".

Stanford responded by tearing into reports that dead people and foreigners may have received the cost of living payment, which arrived in eligible Kiwis' bank accounts on Monday. 

"How many international backpackers got it? They don't know and, the thing is, they don't want to know - they don't want to find out," the East Coast Bays MP said.

"We've asked [Revenue Minister] David Parker for this information and, not only does he not know, he's not going to find out so we may never know - unless the Auditor-General gets involved."

Stanford said Labour "should own up to this mistake".

"Own it and fix it - that's all we want to hear from Michael Wood today is; 'Yes, there's a problem and we're going to fix it because we care about Kiwis' hard-earned cash.'"

Wood said work was ongoing "to make sure the data is as accurate as possible".

"The key thing, though, is that Kiwis get this payment. If you set up a complicated application system, fewer New Zealanders would get the payment and it would cost more."

Wood added the Government was "tackling some very complex and long-term issues" and denied it Labour had a problem delivering.

"Sometimes, we don't get it perfect and sometimes the issues take a long time to work through," he said.