Mooted budget cuts to superannuation contributions could cost investors at least $70,000 in retirement savings.

As things stand, a 45-year-old woman earning $100,000 a year, with a median super balance, could retire on $560,000 at 65 in today's dollars if she salary-sacrifices to the upper contribution limit of $35,000 a year for her last 10 working years, numbers by Dixon Advisory show.