National Party leader Simon Bridges is warning that the "tsunami" of debt in Budget 2020 will have to be repaid, either in higher taxes or by future generations.
But he is welcoming the Government's extension to the wage subsidy scheme.
"It's well-intentioned, but overall it's a heck of a lot of spending," he told reporters yesterday.
"All of that additional spend will result in more debt. That debt will result I think under a Labour Government in more tax, and if not then a legacy for our children and grandchildren where they have to pay it back.
"That's very serious."
BUDGET 2020: THE FULL PACKAGE AND WHAT IT MEANS FOR YOU
• The Budget at a glance
• Audrey Young: Robertson keeps fingers crossed as he gives himself options
• Wage subsidy scheme extended by 8 weeks, now up to $14b
• Devastated tourism sector gets $400m but details are scarce
• School lunch programme boost to feed 200,000 children every day
He said New Zealanders deserved to have more clarity about the $50 billion Covid recovery fund, the centrepiece of Budget 2020.
"There's over $25b that the Minister of Finance can't even say how he would spend right now."
Grant Robertson said there was about $20b unallocated so far, and that may end up being targeted towards the most vulnerable.
National's finance spokesman Paul Goldsmith said there was nothing specific in Budget 2020 about easing commercial rents for businesses, and small businesses in particular.
"They haven't seen that. Instead what we've seen is this big sum they may spend on whatever they like in the election campaign."
Prime Minister Jacinda Ardern said work was still being done to see how to help ease the commercial rent pain.
Goldsmith said some debt was understandable in the extraordinary times, but $140b of more debt by 2024 would be felt for generations.
Bridges added that $400m for tourism, which employs 400,000 people directly or indirectly, seemed at odds with $1.2b for rail.
"That doesn't seem to me to be getting priorities right."
Act leader David Seymour said in his Budget speech in the House there was a lack of detail in the spending, also citing the $400m for tourism.
"The press release I would estimate is $1m a letter. There is so little detail."
He called the $1.1b environment fund the "Barry Crump fund" that would see some people planting pine trees, others pulling down wilding pines, and others culling a wallaby infestation caused by the Government's ban on semi-automatic firearms.
The message to parents of children getting free lunches in schools was that they didn't need to provide their kids with lunches, he said.
"They're [the children] going to grow up in a New Zealand with triple the public debt - $140b (by 2024) borrowed by the Government in their name in this Budget."
He said Treasury's prediction of having no restrictions because of Covid-19 by April next year was a "heroic forecast and borderline fraudulent".
Act has released an alternative Budget with tax cuts, replacing the Resource Management Act, and lifting restrictions on foreign direct investment from OECD countries.
New Zealand First leader Winston Peters used his Budget speech to tell Bridges to "get a haircut and get a real job".
He said the "new normal" in a Covid world was about focusing on New Zealand.
"This means having the ability to grow it and make it, use it, and export it, rather than waste valuable offshore funds importing it."
Green Party co-leader James Shaw said the party's fingerprints were all over Budget 2020. citing $33m set aside for migrant family reunification and $56m for more insulation in the homes of low-income people.
He later told media that he wanted the Budget to gofurther in terms of welfare reform.