The Government says rents won't go up as a result of Budget Day increases to the accommodation supplement, but the Green Party's predicting landlords will feather their own nests.

On Budget Day, Social Housing Minister Amy Adams' view was the increased subsidies wouldn't have a major effect on rents.

"We don't expect it to have a significant impact on market rents, we've asked that question actually, we've been through that in the build up to the budget," she said.

But Green Party Co-Leader Metiria Turei vehemently disagrees.

She said the Government's not addressed the housing crisis with its plans, and instead it'll end up giving $400 million to landlords over the next four years.

"Now what the Government has done is not address the housing crisis but given $400 million to landlords over the next four years," she said.

The ACT Party Leader David Seymour agrees saying basic economics shows that pumping taxpayer money into the rental market will give landlords the chance to put up prices.

He said without a corresponding increase in housing supply, they are making housing a more profitable investment - so actual purchase prices will go up too.

Seymour said the Government would literally be better off spending $360 million on fidget spinners for every New Zealander.