AP - Advocates of legalising marijuana say that New Zealanders are among the world's biggest users of the drug. Green Party researcher Roland Sapsford told a parliamentary hearing twice as much marijuana was used in New Zealand as in Jamaica - which he described as the world marijuana capital, the Dominion newspaper reported Thursday. The committee is investigating the use of the drug as part of a Green Party initiative to decriminalise personal use of marijuana. Studies have shown that 52 per cent of New Zealanders between the ages of 15 and 45 had used marijuana. Green legislator Nandor Tanczos, the first New Zealand lawmaker to admit occasional use of the illegal drug, told the committee that current policy caramelising marijuana use was not working. "The idea that arresting more people is going to bring drug use down is a fallacy," he said. The Greens say people over 18 should not be penalised for using marijuana or growing it in small amounts, but commercial production should remain a criminal offence. The Pharmaceutical Society, an industry group, said nearly 10 per cent of New Zealanders had a drug problem involving marijuana or other substances.