HUNDREDS of unionists and other workers rallied through the streets of Melbourne to mark international workers' day.

The May Day procession, led by a team of bagpipers, wound its way through the city centre before concluding at Trades Hall in Carlton.

Melbourne May Day committee president John Speight said it was an opportunity to pay tribute to the pioneers who played a part in improving working conditions.

''This state was the first state that got the shorter hours in 1856,'' Mr Speight said.

''This is part of a celebration of those victories and also bringing people together for the fights coming on.''

The main theme of this year's march is on workers' right to strike.

Mr Speight said workers were a long way from having the right to strike in protected conditions.

''You've got to jump through a lot of hurdles so workers have got the right to strike,'' he said.

''In some cases they can only strike on the basis of an enterprise bargaining agreement on wages and conditions.''