Customs officers seized half a tonne of herbal cannabis worth $25 million from a Tuen Mun house on New Year's Eve. It was the biggest seizure of cannabis intended for local consumption. After a two-month investigation, about 50 Customs officers raided a house at Siu Hang Tsuen at about 7 pm and seized 435 slabs of cannabis in a mezzanine-floor room. A man aged 24 was arrested outside the house. Customs officers are looking for other suspects. Acting Superintendent Ng Wai-ming from the Customs Drug Investigation Bureau said the drugs had arrived by sea from Thailand three weeks ago. 'We believe the drugs are for local consumption and mainly for supply to the places like karaoke lounges, game centres and nightclubs in the new towns in the New Territories,' he said. 'It appears more youngsters take cannabis because it is cheaper than drugs such as heroin. 'Demand for it rises during the festive period.' The find follows the discovery of 300 kg of cannabis in a San Po Kong factory on December 20. 'The two incidents are not linked,' Mr Ng said. 'But we believe our operations have struck a heavy blow against the supply of cannabis in Hong Kong,' he said. Last year, Customs seized about 900 kg of cannabis, including the New Year's Eve haul. Customs officers' biggest cannabis seizure was in 1996. About 7.2 tonnes of the drug were seized, but the cannabis was intended for use overseas.