Splinter protest groups calling for democracy for Hong Kong are springing up and fast-tracking action plans as student-led demonstrators consider a retreat from the main campsite that has blocked key downtown arteries for more than two months.

Protesters were thin on the ground Monday ahead of an expected midweek clearance of the main camp site at Admiralty, home to government offices and next to the main Central business district.

The "Umbrella Movement" protests have been largely peaceful in their demand for a free vote in the Chinese-controlled city.