CANTON, China, May 23, Reuter - The streets of the southern Chinese city of Canton throbbed with demonstrators on Tuesday night as hundreds of thousands, including Hong Kong and Macau sympathisers, marched to demand democracy.

Students, workers and journalists staged the largest rally in a week-long series of protests as lightning ripped through the skies and painted banners blurred in the streaming rain.

People in the south had previously played a less prominent role in China's wave of pro-democracy protest than their beleaguered Peking counterparts struggling with martial law.

"To start with, we thought it was Peking's business, all that political stuff. But it didn't take long to realise it's our problem too," said a local taxi driver.

"In 40 years of the People's Republic, no one has ever been this rude to the government. It's from the people, from the heart," he said.

Student leaders, waving dripping banners proclaiming the solidarity of Canton, the British colony of Hong Kong, and the nearby Portuguese enclave of Macau, said at least 600 students had crossed the border to join them.

Hong Kong will revert to Chinese rule in 1997 and Macau in 1999. Both have been the scenes of big demonstrations in support of the protesting students in Peking.

Bicycle jams piled up at major junctions as marchers streamed past singing humorous songs attacking hard-line Premier Li Peng, who alienated students by ordering troops into Peking last week.

Some were sceptical about rumours that Li was losing a power struggle with reformist leader Zhao Ziyang.

"We won't believe it until we see it," read one poster, showing Li bound and gagged.

Police kept a very low profile and were unwilling to estimate how many hundreds of thousands were clogging the streets. "Who knows? We just want to let them get on with it," a policeman said.

Despite sodden conditions, the demonstration resembled a carnival parade, with onlookers setting off firecrackers, blowing whistles, clapping and cheering.

"I can't believe it. I really think we might win this battle," said a textiles worker as he watched, perched in the branches of a tree.