Hockey floats more tax ideas

Joe Hockey is persisting with a debate on the merits of dipping into superannuation before retirement in the face of opposition from his own cabinet colleagues.

And now he's thrown out a suggestion that company tax and the GST could eventually be abolished.

The treasurer has floated the idea of superannuation acting as a "shock absorber" at various stages of life, including possibly helping first home buyers get a deposit together.

Prime Minister Tony Abbott welcomed debate on the idea but it's been roundly knocked by Labor, economists and former politicians Paul Keating and Peter Costello.

And Mr Hockey's cabinet colleague Malcolm Turnbull bluntly labelled it "a thoroughly bad idea".

Mr Hockey said ideas around superannuation tax breaks, capital gains tax and negative gearing would be up for further debate when a tax discussion paper is released in April.

That paper will look at Australia's taxation system compared with other countries.

"It's perfectly reasonable to speculate that over the next 20 to 30 years company tax will not be around," Mr Hockey told ABC TV.

"And maybe the GST won't be around either because of international trade."

Mr Hockey insists he's not spruiking the superannuation idea, just fostering debate about how to cope with maintaining quality of life throughout longer lives.