Government not budging on RET offer

The federal government has commended Labor for its latest offer on the renewable energy target, but insists it won't be budging.

Industry Minister Ian Macfarlane instead wants the opposition to have another think about supporting a pared-back 2020 figure.

Labor will back 33,500 gigawatt hours - down from the legislated 41,000 GWh - but Mr Macfarlane told ABC radio on Thursday the government's top limit was 32,200 GHw, which he said would ensure the scheme was sustainable.

Opposition climate spokesman Mark Butler says the government is on its own, with business and the clean energy sector backing a compromise target.

"It's time for the government to move," he told Sky News.