Couples earning up to $180,000 will be able to buy KiwiBuild homes, the government has announced.

Housing Minister Phil Twyford has set out the maximum income cap restricting who will be allowed to buy a home under the programme.

To be eligible, buyers must be purchasing their first home, or be "second chancers" - those people who haven't yet had an opportunity to own their own home or who no longer own one.

They must be New Zealand citizens, permanent residents or those who ordinarily reside in New Zealand, and intend to own and live in the house for at least three years.

The income caps are $120,000 for sole purchasers and $180,000 for couples.

Mr Twyford said people earning that level of income had been struggling to buy in high demand areas like Auckland and Queenstown.

He said 10 years ago they would have been able to afford to.

Cabinet signed off on the eligibility criteria yesterday.

KiwiBuild houses in Auckland and Queenstown will have a maximum price of $650,000 for a three-bedroom home, $600,000 for a two-bedroom home and $500,000 for one bedroom.

Across the rest of the country, the maximum price will be set at $500,000.

The KiwiBuild policy aims to construct 100,000 affordable homes over the next 10 years. The government's beginning with a target of 1000 houses over the next year and another 9000 by 2021.

From today, aspiring first home-owners will be able to register their interest online.

There will be a ballot system for prospective buyers with those whose names are drawn getting the first opportunity to buy the homes they have registered interest in.