Taxpayers are likely to bear only a small portion of the cost of a new $378 million metro rail station underneath Sydney’s existing Martin Place station, after the government completed a deal to sell the air rights above the station to Macquarie Group.

The investment bank will pay $355 million for the right to build towers to the north and south of Martin Place, Transport Minister Andrew Constance announced on Wednesday.

Once the new buildings are complete in about 2024, Macquarie is likely to make another payment to the government to reflect the increased value of the land.