Last weekend, New Zealand customs broke up a drug ring that smuggled up to NZ$17 million (HK$97 million) worth of pseudoephedrine, which arrived over 12 months at Auckland International Airport in machine parts imported from Hong Kong. Ephedrine or pseudoephedrine is a key component in the manufacture of methamphetamine.

It is alleged that a company called EJ Trading imported 145kg of machinery parts, with 10kg of drugs hidden inside each part. Records show EJ Trading made 28 imports between April last year and this April. Auckland police allege 320kg of pseudoephedrine were smuggled.

A customs broker, Bo 'Kevin' Niu, is due to stand trial with co-accused students Lei 'Aaron' Chen, Yixiang 'Ethan' Zhang and Tong 'Ivan' Liu, charged with possession and supply of pseudoephedrine.

Last month, Philippine police arrested three mainland men and a woman, and a Hong Kong man, after a raid on a Manila house which was turned into a methamphetamine factory. Reports said the seized drugs had a street value of US$2.2 million.

These operations dovetail with the International Narcotics Control Strategy Report, provided by the United States consulate general in Hong Kong in March, which pinpoints the mainland as producing large quantities of chemicals that can be used for illicit drug manufacturing.

'It has been reported in recent years that Chinese authorities have continued to seize clandestine methamphetamine laboratories,' it said.

'In the past, the majority of the labs were discovered and/or seized in Fujian and Guangdong provinces. Traffickers continue to use Guangzhou, Shenzhen and Zhuhai in Guangdong province as transit and transshipment points for heroin and crystal methamphetamine exiting China. In addition, Xiamen and Fuzhou in Fujian province are major exit points.'

Apart from its use, methamphetamine manufacturing is also extremely volatile and dangerous. It creates a significant amount of hazardous and toxic waste as a by-product, a spokesman for the consulate general said.

'Typically, after a methamphetamine manufacturer has finished with a clandestine laboratory site, it is abandoned and left for someone else to clean up,' the spokesman said. 'The toxic by-products of methamphetamine production are often left behind, moved, dumped, or buried, which harms communities, public health and the environment.'

Not that this will deter illegal drug operations. The concept of having a methamphetamine-making centre in Hong Kong is still a viable and lucrative proposition.

In last month's raid, customs officers seized finished and semi-finished batches of the drug Ice in liquid and crystal forms with a street value of HK$175 million and four sets of drug-making machines from the factory and two other locations.

Among the seizures was 67.5kg of finished Ice, the first batch the syndicate produced, which was found in a hotel room in the New Territories.

Police said there was no evidence Hong Kong was being used as a drug-manufacturing centre and that this was 'an isolated case'.

'The recent customs and excise case was the first large-scale manufacturing of methamphetamine taking place in Hong Kong,' a police spokesman said. 'This is an isolated case and there is no indication that such illegal operations are on the rise in Hong Kong. There has been no other methamphetamine production centre detected in Hong Kong in the past three years.'

A customs spokesman said: 'We remain vigilant over all forms of drug activities in Hong Kong. We have strengthened co-operation and intelligence exchange with our mainland and overseas counterparts on the trafficking of drugs and precursor chemicals.'

Meanwhile, there is the social aspect of taking methamphetamine in the workplace in Hong Kong. Mobile phones and BlackBerries mean one is never really out of the office and for some, working hours have got longer and the financial downturn means more business has to be done in less time and with fewer people.

'It's just constant pressure to produce,' one city trader said. 'It's not like Hong Kong's white-collar workers can't afford to buy it. It all makes stimulant use something that not only exists, but it'll be on the increase as demands on us get worse.'

Among blue-collar workers, amphetamines and methamphetamine are used to boost endurance such as for night-shift work.

In some countries, Ice is taken by students to get them through late-night cram sessions but that is not believed to be the case in Hong Kong.

'In Hong Kong, we have found Ice is not used in this way. It's too expensive and is only sometimes used by students when they go out partying to relieve the stress of studying,' said Jess Cheung Chun-man, a social worker at KELY Support Group.