UNIONISTS filled Brisbane streets yesterday to celebrate the return of Labour Day to May, amid speculation over the Queensland LNP leadership.

It was the first time the celebration of workers' rights had been held on May 2 since the former Liberal-National government shifted it to October three years ago in line with other states.

This year it coincided with reports Lawrence Springborg's future as Queensland LNP leader was under threat over his reported failure to negotiate with crossbenchers to stop Labor's from reintroducing compulsory preferential voting.

Premier Annastacia Palaszczuk attended a Labour Day march in Barcaldine, where the Australian Labor Party began out of a series of shearers' strikes 125 years ago, acccompanied by wheelchair-bound former prime minister Bob Hawke.