Richard Morris, from Ancre Hill estates winery near Monmouth, said other countries with similar climates, such as Nova Scotia in Canada, have already developed a successful wine industry.
There are about 17 vineyards in Wales, according to the Welsh Vineyards Association.
Wales produces around 100,000 bottles of wine annually.
He told BBC Radio Wales' Country Focus programme: "We're predicting by 2035 that we'll have four to six wineries in Wales, that we'll have about 50 vineyards.
"That's based on the growth of the wine industry in Nova Scotia, for example, on the eastern seaboard of Canada.
"It's a massive industry there and Wales can quickly get to that level, I'd say, within 10 to 15 years."
The company's selling point is that the wine is "bio-dynamic" which means only natural products are used in production and the broader eco-system is considered.
And it has recently started supplying a wholesaler in the historic wine growing region of Bordeaux, France.
"I know everybody laughs at this but it's the honest truth - we've just had a wine order from a wholesaler in Bordeaux who's interested in selling good wine from around the world," he said.
According to the Welsh Vineyard Association, Welsh wine started with the Romans, who are thought to have brought grapes and wine-making to Wales.
Then, in 1875, Lord Bute planted a commercial vineyard at Castell Coch, near Cardiff.
From just a few vineyards in the mid-80s there are now about 17 across Wales and Wine Trail Wales has also been launched to show the part they can play in the tourism industry.
Welsh vineyards are producing around 100,000 bottles of wine a year, up 70% in the decade.
White Castle vineyard near Abergavenny, Monmouthshire, has been going since 2008. It offers tours and tastings as a way of selling its wines.
Ancre Hill estates is the latest to expand with another 11 acres (2.8 hectares) of vines.
Its owners say south facing land with sheltered areas and good drainage provide ideal conditions for Pinot Noir and Chardonnay grapes.
And each field is expected to make 20,000 bottles.
Wales could have 50 vineyards in 20 years' time, according to one grower who is selling Welsh wine to France.