More than half a million Queenslanders signed up for a postal vote before the March 28 council elections, as early voting hours are extended and the electoral commission prepares for a very different election day than usual.

The deadline for requesting a postal vote was 7pm on Monday, triggering the Electoral Commission Queensland's website to crash and forcing people to email directly to request a postal vote form.

Minister for Local Government Stirling Hinchliffe. Credit:AAP Image/Darren England

In all, more than 540,000 people requested a postal vote and thousands more took advantage of early voting booths opening statewide on Monday for Queensland's 77 councils.

Queensland has about 3.2 million registered voters. Voting is compulsory, with a fine of $133.45 for not voting.