Disenchanted high-income earners are considering spending more of their wealth and falling on the part-pension if the government's plan to reduce the cap on low-tax super contributions goes ahead.

At the moment, savers who earn less than $300,000 and are under 49 can put up to $30,000 into super per year before tax at a rate of 15 per cent. Those who earn more than $300,000 have to pay an additional 15 per cent tax (30 per cent), but it has been speculated the government wants to reduce that threshold to $180,000. Labor said it would reduce the threshold to $250,000.