Levying the tax on suppliers made the collection of the tax simpler for both consumers and Customs, which did not have the resources to collect GST on all goods under the current model.
However, it did create complexity for suppliers because there were several boundary issues to consider,
Mr Stevenson said.
Those issues included whether the purchaser was GST registered, the value of the goods, and whether a re-deliverer or marketplace were collecting the tax.
"It will mean a systems investment for re-deliverers, marketplaces and suppliers."
The Government announced yesterday it planned to impose goods and services tax on small online retail purchases which had previously been ignored by officials because it was too expensive to pursue.
From October next year, offshore suppliers would be required to register, collect and return New Zealand GST on goods valued at or below $400 supplied to New Zealand consumers.
Mr Stevenson said the proposed method to collect GST on low-value imported goods was modelled on the Australian method. International suppliers had some experience in complying with similar rules.
"This change on its own will not increase domestic retailers' competitiveness. People buy online from overseas suppliers for a number of reasons including convenience and a greater selection - and the GST savings are insignificant to many purchasers."
BusinessNZ chief executive Kirk Hope said New Zealand retailers would welcome the move, and there would also be benefits for customers.
It would not mean extra compliance for New Zealand customers, and it would provide some certainty around pricing of imported goods.
By treating lower and higher-value goods the same for GST purposes, the scheme would be consistent with the rest of New Zealand's broad-based, low-rate GST system.
Inland Revenue's consultation on the proposal would help work through any issues with the proposed scheme.
The system would take time to develop and more work was needed on policing of overseas providers and their reporting systems for tax collection, he said.
"We have treaty arrangements with other countries to allow us to request them to collect unpaid GST on New Zealand's behalf, and we need to develop joint registration and collection systems with those countries."
Once the system was fully developed, a comprehensive GST system, aligned with other sales tax systems internationally, would be developed, Mr Hope said.
Revenue Minister Stuart Nash and Customs Minister Meka Whaitiri announced the changes at boutique Wellington bookstore Unity Books.
Mr Nash said in a statement small businesses such as bookshops had convincingly argued they were penalised by a system which was badly out of date.
"It's particularly difficult for very small shops outside the main centres."
The Government's Tax Working Group was allowed to consider the issue of imposing GST on low-value online purchases and could make an early recommendation given the train of work already under way.
Tax Working Group chairman Sir Michael Cullen wrote to Finance Minister Grant Robertson, Mr Nash and Ms Whaitiri saying the non-collection of GST was an increasing problem which the group considered should be addressed quickly.
There was no in-principle reason why GST should not be collected on imported goods consumed in New Zealand just as it was collected on domestically sold goods consumed in New Zealand.
The current non-collection of GST resulted in a competitive disadvantage and unfairness for New Zealand retailers and resulted in an increasing amount of GST revenue foregone by the Government, he said.
