Buying that second or third investment property to help fund retirement may be less attractive in future with Labor opening the door to a policy of tightening up negative gearing tax concessions, if elected.

The possibility of less favourable rules for wealthy property investors came as Labor formally unveiled its proposed tax increases for high-end superannuants.

Shadow treasurer Chris Bowen. Credit:Andy Zakeli

But any negative gearing change, which has not been committed to, would have to be prospective in its application and would not affect existing landlords, said shadow treasurer, Chris Bowen.

It would also need to be tailored to achieve the twin goals of returning funds to the federal budget and ensuring ongoing supply of new housing stock into the rental and purchasing markets.