Around 230,000 Australians would receive annual tax bills up to $4125 higher if the threshold at which high-income earners pay more tax on super was lowered, but such changes may also improve equality within the $3.3 trillion system, economists and consultants say.

People earning more than $250,000 across combined salary, super and any fringe benefits are subject to an additional 15 per cent tax on their concessional contributions under division 293 tax rules.