BULLDOZERS rolled in to some of the last remaining koala habitats on the South Coast yesterday, marking the start of what police fear could be a divisive logging operation.

Forests NSW workers plan to log about 180 hectares of native eucalypt forest from the coast north of Bermagui, for a mixture of wood veneer products and woodchips.

But environmentalists and local residents are planning a long campaign to keep the forest undisturbed.

New studies by the NSW Department of Environment and Climate Change show only a handful of koalas remain in the district - perhaps a dozen out of a Far South Coast population once counted in the thousands.

None have been found within the logging zone itself, although the discovery of koala droppings suggest the animals may move through the area from time to time.

The NSW Government said logging in the two zones north of Bermagui would not affect the koalas.

"Extensive surveys have shown there are no koalas in the two compartments involved in the current harvest and few in the South Coast area," the Primary Industries Minister, Ian Macdonald, said in a statement.

A coalition of local environment groups, called the South East Region Conservation Alliance, said that koalas may still use the logging zone, and said a koala management plan for the district was not yet complete.

"These public forests are of critical importance to the survival of the remnant of the koala population," said a spokesman, John Hibberd.

"The remnant here is thought to be about 10 to 12 individuals, and there's a very real chance that the loss of this habitat, together with the pressures of climate change and drought, could see them die out," Mr Hibberd said.

Koalas are known to travel up to 50 kilometres in search of mates or food. Protestors, some of whom volunteered in a koala-spotting survey over the last two years, believe the logging would make the few remaining animals more isolated and vulnerable to bushfires.

Workers from Bruce Mathie and Sons, the company which has a contract from Forests NSW to carry out the logging operation, have been instructed to halt work if any koalas are sighted.

As protestors established a camp in the forest yesterday, police put in new temporary speed limits on nearby roads and issued a warning against violent protests, in light of recent logging-related incidents in Tasmania, which saw an activists' car smashed with a sledgehammer and a camp destroyed with petrol bombs. Police from the Public Order and Riot Squad were patrolling entrances to the state forest at Bermagui yesterday.

The South East Region Conservation Alliance said logging in native forests is no longer necessary because Australia has enough mature plantations to meet all it's domestic wood needs.

The Bermagui state forest was logged 20 years ago, and clear-felled in 1928.