A delay in increasing the superannuation rate will "almost inevitably" mean higher wages, federal treasurer Treasurer Joe Hockey has said, while also conceding employers could pocket the saving instead of passing it on to workers as wage rises.

The Abbott government struck a deal with the Palmer United Party on Tuesday to make good on one of its key election promises to repeal the mining tax. As part of the bargain, the government agreed to delay the increase in the compulsory superannuation rate from 9.5 per cent to 12 per cent to 2025 instead of 2019.

Mr Hockey on Wednesday defended his deal, which is being criticised by the superannuation industry and the Labor opposition as a hit to workers, saying the delay would amount to higher wages because "either it comes into workers' pockets or goes into superannuation, it's one or the other".