When French winemaker Laurent Metge-Toppin first saw the floating vineyards of Thailand's Chao Phraya river delta, he knew he would struggle to make a wine worthy of his vintner ancestors in the Cotes du Rhone.

Seared by a tropical sun and lashed by monsoon rains, the delta's islands of vines, rooted in soil but separated by narrow canals, were a stark contrast to the rolling hills of French wine country.

"I knew we couldn't make a Bordeaux here, but I thought we could still make a unique wine," Metge-Toppin said on a tour of the Siam Winery, an hour's drive south-west of Bangkok.

"Our idea was to make a wine to drink with Thai food."

The result, 10 years on, is the Monsoon Valley range of reds, whites and roses created to complement the fiery flavours of Thai cuisine.

The delicate, dry, low acidity vintages are exported to 14 countries and have won plaudits from critics initially suspicious of "new latitude" wines produced outside the traditional heartlands of winemaking.

"The Monsoon Valley wines are fascinating: clean, light, dry and very drinkable," wrote British wine expert Hugh Johnson.

The grapes, the local dark- skinned Pokdum for red wine and Malaga Blanc for white, are bought from farmers who ply their wooden boats along the canals and handpick the fruit at dawn.

Siam Winery is one of six Thai companies producing wine, joining winemakers in Brazil, China, India and Kenya challenging the dogma that wine can only be produced in temperate regions.

"For years we have drawn two bands around the globe, roughly between latitudes 30 and 50, to denote those parts of it deemed suitable for viticulture," Jancis Robinson, a respected wine critic and writer, said on her website.

"But all this is changing fast," she wrote.

"Advances in refrigeration and irrigation techniques, not to mention much greater control over how and when vines grow, have opened up to the grapevine vast tracts of the world previously thought unsuitable."

The abundance of water in the Chao Phraya delta, just 13 degrees north of the Equator, means no irrigation is needed, while the tropical climate allows for two harvests per year.

But wine must be kept cool throughout production and storage by means of expensive refrigeration, not necessary in established winemaking regions where temperatures dip after harvest.

Another headache for Thai vintners is tax.

Thailand is one of the most expensive places in the world to buy wine, with taxes of nearly 200 per cent on locally-made vintages and a swingeing 360 per cent on imported wine.

A bottle of Scotch whisky, taxed at around 37 per cent, is the most likely accompaniment to a Thai celebratory dinner - a source of frustration for winemakers who say high taxes have choked domestic wine sales despite a fast-growing middle class.

"Strong growth at home is vital to us," said Kim Wachtveitl, Siam Winery's business development director. "But high taxes make it difficult to get people to switch to wine."

It is cheaper to buy a bottle of Monsoon Valley white in London, at $US9, ($NZ11.89) than in Bangkok, where the same wine costs $US11.70.

So for now, the focus for Siam Winery - owned by businessman Chalerm Yoovidhya, whose family sold the energy drink Red Bull to the world - is on international growth.

Specifically, it is targeting Thai restaurants across the globe, hoping to become the house wine of choice.

"If you go to a French restaurant you want French wine," said Metge-Toppin.

"So we say why not Thai wine for Thai food?"

The white Malaga Blanc, with aromas of lemongrass and watermelon, is the perfect complement for green curries, the winemaker said. The red, made from Pokdum grapes blended with Shiraz and Black Muscat, suits red curries and satays.

Last year, Siam Winery exported around 250,000 bottles, 70 per cent of its output, to Europe, Japan, Australia, New Zealand and the United States.

Its biggest export market is Britain, where it sells to 350 Thai restaurants.

With an estimated 10,000 Thai restaurants worldwide, there is plenty of room for growth.

Metge-Toppin is reluctant to predict the future: "In France we have a thousand years of history making wine. Here we are learning all the time. It is all new territory for us."

Some wine critics are cautious too, but concede that the same scepticism once surrounded the now highly-regarded "new world" wines of the United States, Australia, South Africa and New Zealand.

"I still find it hard to believe that new latitude wines will ever be seriously good," wrote Jancis Robinson.

"But then that's what was said about New World Wines not that long ago." Reuters.