The increasingly popular drug 'ice' - 160kg of which were seized yesterday can give users a kick that lasts 12 hours and is more addictive than heroin, police said yesterday. About a tenth of a gram of the drug, a synthetic stimulant, is understood to give users a feeling of extreme physical, mental and sexual potency. If one gram was taken at once, the feeling could last 24 hours, a source said. 'The effect is stronger than heroin,' Narcotics Bureau spokesman Superintendent Bernard To Hon-ki said. 'More and more people are addicted to it and are consuming daily.' Ice, or methamphetamine hydrochloride, was usually sold in crystalline form but was sometimes a liquid. Mr To said its retail price was now $507 per gram. The source said one 'line', or about 0.1g, either smoked off foil or added to a cigarette, provided a 'high' more powerful than any other stimulant drug. But as the drug wore off, users would become irritable and depressed, suffered cold sweats, shaking and loss of appetite. The side-effects could last days, depending on the amount of ice consumed. Mr To said people could become addicted to ice after using it just once. Like most drugs, it was particularly popular with people under 21. The drug was first produced by a Japanese chemist in 1919. Police suspected most ice in the SAR came from the mainland or laboratories in the Golden Triangle, on the Thai border with Laos and Burma.