Shakey polls?

The Galaxy poll of 4000 voters in 20 marginal seats puts coalition support at 51.4 per cent to Labor's 48.6 per cent on preferences.

But the Galaxy poll finding is not supported by two leading analysts.

ABC election analyst Antony Green says he comes up with a different result when entering the projected Galaxy swings into his election calculator.

"Someone has made an absolute howler in trying to turn polls in 20 marginal seats into a national figure," the ABC expert wrote on his blog, adding whoever calculated the vote committed two serious errors.

"First, the figures are for four electorates, not the states. Second, while the state samples are the same size, the state populations are not," he said.

Mr Green says his calculation from the Galaxy poll shows Labor at 51 per cent, not 48.6 per cent.