Work has started on updating consumer law to provide more protection for sales made on internet auction sites.

Consumer Affairs Minister Heather Roy said the law had not kept pace with the growth in internet trading and it had become a significant issue.

She has asked her officials to consider whether the current consumer laws could be simplified and updated to take in internet trading.

She said some sites such as Trade Me had their own rules, but there was no wider protection if a deal went wrong with goods sold on some other sites.

Updating the law to include internet auction sales will form part of a wider review of consumer law.

Mrs Roy said she was aiming for a "one law, one door" approach to consumer law - so one basic law covered all transactions between a buyer and seller, and aggrieved parties could go to one place to get redress.

There were currently numerous different tribunals and courts which dealt with different situations.

She said the Commerce Commission tended to take on major cases only.

"The ones slipping through are the small ones, the mum and dad transactions, made in good faith, but there is so much confusion about where to go people tend to give up. I want easier access to redress.

While the Fair Trading Act and Consumer Guarantees Act were reasonable and broad based, there were others such as the Door to Door Sales Act, and Layby Sales Act which dealt with specific circumstances.

Consumer NZ chief executive Suzanne Chetwin said the group had long called for the law to be updated to cover private sales online.

She was also keen to see greater protection for second hand car sales between private people.

But she was unsure whether a major overhaul of New Zealand's consumer law was required. She said it was already strong and while some acts needed updating, the two main one - the Consumer Guarantees Act and Fair Trading Act - tended to cover most instances.

She said most people also tended to know about bodies such as the Disputes Tribunal.