Treasurer Jim Chalmers has refused to budge on his controversial plans to raise taxes on people with more than $3 million in superannuation, even as he signalled he was open to cutting income taxes as part of wider tax reform.

In a speech delivered to the National Press Club in Canberra on Wednesday, Chalmers said Labor was willing to overhaul the tax system to reduce its growing reliance on income tax while ensuring the government can raise enough money to plug the budget deficit.