EXTENSIVE crowd control measures will be in place on Sunday night when more than 500,000 people are expected to flood both sides of Victoria Harbour for the Lunar New Year fireworks display. All officers on duty will be alert to any signs of trouble, police said yesterday. Borrowing a page from the Bokhary report and from past experience, police in Wan Chai and Tsim Sha Tsui will halt the influx of people into areas if overcrowding begins. Loud hailers and public address systems will also be used to aid crowd control. Those attending the fireworks are discouraged from bringing any spray foam. Police will confiscate the spray cans if necessary, Wan Chai district police commander, Chief Superintendent Dick Lee Ming-kwai said. The spray cans were cited in the Bokhary report of the Lan Kwai Fong disaster as a cause of the slippery road surface. An estimated 80,000 people will line the Wan Chai harbour front on Sunday night while another 40,000 will watch the display from the area's office towers and hotels. A force of 560 officers, backed up by 45 Civil Aid Services (CAS) members and three first-aid stations, will handle crowd control. Tsim Sha Tsui, where more than 400,000 people are expected to show up, will be patrolled by more than 1,500 officers backed up by another 45 CAS members, said the district's police commander, Chief Superintendent Gilberto Jorge. Both waterfronts will be closed off to vehicular traffic while the flow of pedestrians will be strictly monitored and controlled. Buffers will also be set up to separate the crowds from the edges of the water, police said. Police are currently studying the Bokhary recommendation that crowds be measured by the ability of officers to move about freely. It is not expected to be used this time, Mr Lee said. Water traffic will also receive special attention from the Marine Department. Speed and entry restrictions placed around the fireworks barges were put in place following a mid-harbour collision two years ago which killed two men. Elsewhere in the territory, a ''tidal flow'' system will be introduced at the Wong Tai Sin Temple where thousands are expected to visit during the New Year period.