PANAJI, India, Dec 27, 2007 (AFP) - Tourists are cancelling holidays to the Indian beach resort of Goa over fears of violent protests against government plans to build more industrial parks here, an official and a hotelier said.

Opposition political parties and environmental groups have set a Friday deadline for visitors to leave the former Portuguese enclave on the Arabian Sea.

"No one wants to harm the tourists but we cannot assure our agitation would be peaceful," said Siddhanath Buyao, secretary of Goa's Movement Against SEZ, which opposes the parks known as Special Economic Zones.

"We are requesting them to leave Goa by December 28 as the protest may turn ugly in the days to come," Buyao warned in the local capital Panaji.

According to official figures, half a million tourists were booked to travel to Goa between December 1 and the first week of January.

Goan chambers of commerce and industry said last-minute cancellations by prospective travellers were growing.

"We have been getting calls from hoteliers about cancellations and we are urging the state government to intervene," said chamber vice chairman Manguirish Painaiker.

Goan hotelier Prasad Salgaonkar said mainly domestic travellers were cancelling.

"We have recorded 40 percent cancellations in just the past two days because of this anti-SEZ issue," Salgaonkar said Wednesday.

Goa has already approved three SEZs spanning 619 acres (250 hectares) in a bid to attract major investment.

Eight other such enclaves spanning 1,917 acres (776 hectares) are in the pipeline, the Goa Industrial Development Corporation said.

No figures were available for the impact on foreign tourist arrivals, but Goa accounts for nearly 12 percent of the four million tourists who visit India yearly.

The Goa unrest has not been widely reported, unlike protests which have left 34 people dead this year in West Bengal over an SEZ in the eastern Indian state.

The Goa administration, run by India's ruling Congress party, has called on protesters to halt their campaign and promised security to visitors.

So far, India has approved 366 SEZs that have brought in 477 billion rupees (12 billion dollars) in overseas investment.