Phil Twyford has defended the Government purchasing seven unsold KiwiBuild houses and said he's "giving thought" to introducing a rent-to-buy scheme.

Twyford, the Housing Minister, said in Parliament there had been no sales of the seven KiwiBuild homes on the market in Canterbury so far, and confirmed three have been bought by the Government.

"Three of those Canterbury homes have been bought by the Government and that's in the context of a contract with Mike Greer Homes that is delivering 104 affordable homes for first home-buyers."

Four other unsold KiwiBuild houses have been purchased in Auckland.

The Government purchased them under its 'underwrite' promise to the developer to either purchase unsold KiwiBuild houses outright or top up any shortfall should the developer sell them at a discounted price.

The underwrite is only triggered if the KiwiBuild houses do not sell within 60 days.

National's housing spokesperson Judith Collins asked the Housing Minister in Parliament why he underwrote already-built and marketed houses after officials had advised him that there was an oversupply of housing in Canterbury.

Twyford replied: "I'm advised that none of those houses were built at the time I authorised [the Ministry of Housing and Urban Development] to begin negotiations with Mike Greer."