The Coalition has given the green light for the privatisation of Medibank Private, which will see the country's largest private health insurer listed on the Australian Securities Exchange before Christmas.

The government-owned insurer is expected to fetch a market value in the order of $4 billion when it lists in December.

The insurer's share market listing is going to be the biggest float since the QR National privatisation four years ago. Credit:Glenn Hunt

The timeline for the float, which will be the biggest since the $4.6 billion privatisation of rail freight business QR National in 2010, was outlined in a statement released by Finance Minister Mathias Cormann's office on Friday afternoon.

The government has decided to proceed with the sale of Medibank Private "subject to market conditions", the release said.