Changes to New Zealand's tax laws have been passed through Parliament.

The Business Tax, Exchange of Information, and Remedial Matters Bill has support from all sides, with opposition MPs only wishing it went further on the issue of foreign trusts.

It includes some changes that will tighten foreign trust disclosure rules, recommended in the Shewan Report commissioned by Government in response to the Panama Papers revelations last year.

Revenue Minister Judith Collins said it also makes it easier for small businesses to pay their taxes.

She said it introduces a new option for calculating provisional tax, and reduces compliance costs for small businesses.

But Labour's finance spokesperson Grant Robertson said we should be aiming for the highest level of transparency here - by introducing a searchable public register.

"We do it for charitable trusts, we do it for companies - there is absolutely no reason why we shouldn't shine the light on what is going on here and do that when it comes to foreign trusts."

Labour and the Greens supported it but again accused the government of initially failing to acknowledge that any changes were needed, and then taking too long to respond to Mr Shewan's report.

New Zealand First's revenue spokesperson Fletcher Tabuteau also thinks there's still a gaping hole in the Government's tax legislation when it comes to foreign trusts.

He said while he's been surprised by Government's genuine efforts to adopt parts of that report, they haven't fixed the legislation.

"That allows the same individuals, the same international corporates, the same criminals to use New Zealand as a way to hide money, to launder money even. So we still have that problem."

Additional reporting by NZ Newswire