KUALA LUMPUR: At Malaysian e-cigarette outlet Vape Empire, customers kick back and puff out thick, aromatic clouds of vapour in funky flavours like Horny Mango and Creamy Suckerz' Banana Anna.

"Vaping" is soaring in popularity in Malaysia, the largest e-cigarette market in the Asia-Pacific region, but authorities are threatening to ban the habit for health reasons — a move that has sparked anger from growing legions of aficionados.

Backing a ban, Malaysian religious leaders this month declared a fatwa on the "un-Islamic" habit, but it remains to be seen whether the decree will dampen enthusiasm.

"The business is growing very fast because there are many people trying to convert from tobacco smoking to vaping," Vape Empire's co-founder Muhammad Sharifuddin Esa said, adding that his business has expanded to 57 locations since it opened just two years ago.

The pastime has proved a particular hit in the moderate, Muslim-majority nation, where other vices such as alcohol and drugs are especially frowned upon.

Now several Malaysian states say they may impose a ban from January 1 and have threatened to stop issuing new merchants' licences — a potential blow to a sector worth an estimated $650 million last year, according to reports.

Health risks debated

The industry, which is expected to grow by more than 13 percent year-on-year to 2025, is currently unregulated, and many say forbidding e-cigarettes — already outlawed in Thailand and Singapore for health reasons -- is a big mistake.

"The government must regulate and not ban, because vaping is the future," Sharifuddin said.

Research on health risks remains split and like Malaysia, few countries have introduced national legislation to regulate the sector.

The devices function by heating flavoured nicotine liquid — or e-juice — into a vapour that is inhaled, much like traditional cigarettes but without the smoke.

Some experts warn vaping can produce cancer-causing formaldehyde and one US study said vaping is up to 15 times more harmful than traditional tobacco smoking. The World Health Organization has called on governments to ban the sale of e-cigarettes to minors.

But other research suggests vaping is safer than smoking cigarettes and manufacturers tout them as harmless aids to quit tobacco.

Enthusiasts in Malaysia say banning the habit doesn't make economic sense.

"Vaping communities are fighting for their rights because the vape scene actually brings profits to the country," said Muhammad Imman, marketing manager of the colourfully named Fcuking Flava vape shop, one of thousands that have popped up across the country.

Marketers cater to local tastes, selling e-juice flavoured with snake fruit, lychee and even durian, the notoriously pungent Southeast Asian fruit.

The juices are marketed like single-malt whiskies or perfumes, as seen at a recent vaping convention in Kuala Lumpur, their creators extolling organic and other premium ingredients.

Aficionados gather daily in Malaysia's vape shops, sometimes for "cloud chasing" competitions to see who can produce the biggest vapour puffs and to show off vape prowess by blowing rings into the foggy air.