National Party housing spokesperson Judith Collins is accusing Housing NZ of pushing first-home buyers out of the Auckland market.
At a select committee hearing Ms Collins said Housing NZ was buying homes for its stock direct from real estate agents at above market price.
Ms Collins asked the agency's chief executive Andrew McKenzie if the agency was cutting first-home buyers out of the market.
"I wouldn't say that we're cutting out of the market," Mr Mckenzie said.
"What we're doing is, there are houses that are available, and we are buying them, so people who need a home to live in can live in that home.''
He said homes were not being built fast enough to meet demand so they were buying houses where necessary.
Ms Collins said she heard in her electorate in Papakura that the agency had an arrangement with real estate agents where it was told directly when a house was about to go on the market and a price was negotiated to buy it.
"The fact is we have people who have been saving for years, who are going through all of the hoops they can to buy their first home, and they're being crowded out by someone with a huge chequebook, and a relationship with agents that says 'come and see me first and I'll give you a bit more'.''
Ms Collins said the houses being purchased are in the $650,000 - $900,000 range, which was crowding out those looking for affordable homes.