Greens lodge formal complaint over LNP ads

The Queensland Greens have lodged a complaint with the electoral commission over a Liberal National Party advertisement urging voters to ditch the preferential voting system.

The ad asks Queenslanders to "just vote one" for the LNP when they head to the polls on Saturday.

"Queensland's optional preferential vote system is risky," the voice-over says.

It then warns voters against numbering every square on their ballot papers, predicting "hung parliament chaos" if the ALP, the Greens, Katter's Australian Party and Palmer United Party are allowed to strike preference deals.

Greens lead spokesman Dr Charles Worringham said the ads were undermining fair democratic process in Queensland by explicitly asking voters to number a single box.

"It is deeply disappointing that the LNP, with their endlessly repeated claims of being 'strong', are asking all voters to vote in the weakest possible way," Dr Worringham said.

The Greens lodged their complaint with just two days of the election campaign remaining.