Duplicating the M1 could cost $2.4 billion, according to a costing released by Labor.

On Tuesday, Opposition Leader Tim Nicholls launched a petition for a second M1 but he would not commit to building it if the Liberal National Party won government.

The LNP has launched a petition calling on the government to duplicate the M1.

The first stage of the second M1 would be along an already preserved corridor extending 36.5 kilometres between Stapylton-Jacobs Well Road at Stapylton and Nerang-Broadbeach Road at Nerang, at a cost of $500 million, Mr Nicholls said.

But the Department of Transport and Main Roads estimated the overall cost of the project between Stapylton and Nerang to be at least $2.4 billion, including the cost of land.