The bill to allow the partial sale of five state owned companies has passed its second reading in Parliament after a heated debate.

The Mixed Ownership Model Bill would allow the sale of part of power companies Mighty River Power, Genesis and Meridian, coal miner Solid Energy and Air New Zealand.

Newstalk ZB reports National, Act and United Future voted for it, allowing it to pass by 61 votes to 59.

It now goes to committee stage where opposition parties are expected to propose hundreds of amendments to try to delay the bill's passage.