Queenslanders are tipped to vote against giving state politicians an extra year in power and many seem unaware or unexcited about having their say.

But the referendum on four-year fixed parliamentary terms, which coincides with local government elections on March 19, is expected to go down to the wire.

A Galaxy poll of 540 Brisbane voters this week showed although 48 per cent wanted four-year terms, 35 per cent were opposed and 17 per cent were undecided.

Traditionally, undecided voters back the no case in referendums, which is a reason why Griffith University political analyst Dr Paul Williams believes the referendum will likely fail.