Hong Kong civil servants returned to work at the government's headquarters Monday as pro-democracy protests which have paralysed the area for more than a week subsided in the face of a deadline to disperse.

Dozens of workers streamed along a footbridge and into the Central Government Offices complex in the harbourside Tamar district, an AFP reporter saw. Several hundred demonstrators remained in the area, well down on past numbers.

A knot of protesters partially blocked the entrance to the complex with barricades, but kept a narrow section open to allow the officials to pass through.

"I'm happy the protesters opened the barriers today," one female civil servant said as she pushed through a crowd of reporters. "I need to work!"

Another who gave her name as Ms Cheung said: "I support the protesters and I have the right to support them after work".

The crowds of protesters have been swelling and subsiding on a daily basis since their campaign began, but dwindled to their lowest point early Monday as many had feared the police would use force to clear them.

The city's embattled leader Leung Chun-ying had warned he would "take all necessary actions to restore social order" if key thoroughfares were not cleared for business on Monday, after a campaign for free elections saw tens of thousands pour onto the streets.