"There will be all sorts of digital payment systems in the future like digital money and PayPal and digital coin payment systems - how would you track those?"
However, he said the retail sector made a good point and he would wait for the working group's findings before ruling out such a change.
"I think they've got a valid point but we do not want to put a regime in place that puts a whole lot of extra cost and hassle to the consumer.
"... You could be bringing in a $10 item and have to go to the airport to fill out forms and pay your GST and so on and that would just make a nonsense of it."
Retailers Association chief executive John Albertson disagreed and told RNZ there were ways it could work.
"As the whole payment system moves into the electronic world where virtually every offshore purchase that's made is done on either a credit card and through PayPal we believe there is a way through the electronic processing to actually be able to clip the ticket for the government and add the GST on.
"At the moment the government are basically subsidising offshore retailers to the tune of in excess of $200 million per year. I think that's worth collecting."