Happy birthday, Cloudy Bay. As the first grapes of 2010 are picked in Marlborough, New Zealand’s largest wine region, the country’s most famous winery is celebrating its 25th anniversary.

Who would have guessed, back in 1985, that a sauvignon blanc with an Australian owner, an English winemaker (albeit one educated Down Under) and a name that sounds like a B&B in Dorset would become such a hit? And to think that they nearly called it Farewell Spit . . .

Cloudy Bay is a brilliant piece of marketing. In the early days it was a great and groundbreaking wine, too. It’s still perfectly drinkable, but at £18.99 it is ludicrously over-priced and often outclassed by the competition, including Greywacke and Dog Point, both of which are made by former employees. Now owned by a French luxury goods empire, which has pushed production way over 100,000 cases while continuing to trade on the illusion of scarcity, Cloudy Bay is not what it was.

The success of Cloudy Bay helped to create the Marlborough sauvignon blanc phenomenon. To wine drinkers who were tired of thin, flavourless sancerre and pouilly-fumé, the bungee-jump-into-a-gooseberry-bush style of Kiwi sauvignon was a revelation. Wine producers love it, too. Not many of them manage to charge £18.99 a bottle, but Marlborough sauvignon is still one of the most profitable wine styles in the world, fermented, bottled and on the shelf within months of the harvest.

But has the whole thing gone too far? So many people saw an opportunity to make money out of Marlborough sauvignon — still a rarity in the capital-intensive wine business — that now there’s too much on the market.

Tankerloads of 2008 and 2009 were sold off in bulk to Australia and the UK, pushing the price down to £4.99 or less. Some of these cheap deals are worth buying — Majestic’s 2009 Fairhall Cliffs Single Vineyard Sauvignon Blanc (£4.99 each for two, 13 per cent) is pretty tasty — but most are over-cropped and profoundly mediocre.

When it’s good, I love Marlborough sauvignon, but its ubiquity has overshadowed New Zealand’s other styles. More than 75 per cent of the Kiwi wine we drink is sauvignon, and nearly all of that comes from Marlborough. To many consumers, New Zealand and sauvignon blanc are synonymous. And as the price of the latter has tumbled, so it has begun to damage the image of the former. If New Zealand weren’t such a clean, green place, it would surely be tempted to tip a few million litres into the Pacific.

New Zealand is changing faster than any other wine-producing country in the southern hemisphere. It’s only in the past 20 years that it has made world class wines, but they get better with every vintage. They will never be cheap — New Zealand’s average bottle price is still £6.12, even with all the sauvignon discounts — but quality and value for money are generally high and often outstanding.

Sauvignon aside, the grape that gets most of the coverage is pinot noir. Rightly so. New Zealand pinot is now a match for anything but the best red burgundies and, under £20, has no competitors for flavour and consistency. We are now seeing the development of regional styles from Central Otago, Martinborough, Marlborough and Canterbury, mirroring those of different villages in Burgundy to a degree, and the emergence of complex wines with the ability to age.

The roll call of suitable grapes doesn’t stop there. New Zealand has always produced really good chardonnay, but now it’s added off-dry riesling and pinot gris, the latter made in an Alsatian rather than an insipid, might-as-well- be-water Italian style. Throw into the mix gewürztraminer, semillon, chenin blanc, viognier, sparkling wines, cabernet/merlot blends and peppery, cool climate syrahs that wouldn’t look out of place in Côte Rôtie and you have a wonderfully vibrant wine scene.

Cloudy Bay makes very good wines from several of these varieties. Indeed, I’d go so far as to say that its mass-produced sauvignon blanc is its least interesting wine. If you want to celebrate that 25th anniversary with a bottle from New Zealand’s most iconic winery do it with a pinot noir, a sparkling wine or a gewürztraminer instead.

2008 Vidal Riesling Marlborough (£8.99, or £7.19 by the mixed case, 12.5 per cent, Oddbins) Just off-dry, but you barely notice the sweetness, such is its acidity. Unoaked and refreshing with notes of apple, pear and peach and a tangy, crunchy finish. Just the thing with Thai or Chinese food.

2008 Tesco Finest Marlborough Pinot Noir Highfield Estate (£8.99, 13 per cent, Tesco) Put this up against a sub-£10 pinot from anywhere else in the world and it will triumph. It’s quite a developed style, with flavours of dill and wild strawberry, but is a delicious introduction to the joys of Kiwi pinot.

2009 Villa Maria Clifford Bay Reserve Sauvignon Blanc Awatere Valley (£13.27, 13.5 per cent, Sainsbury’s; £14.99 but £9.99 until April 24, Oddbins) The Awatere Valley in Marlborough makes leaner styles than the Wairau plain, but they are still delicious. Mange tout and green bean notes give it a crispness.

2008 Mount Difficulty Roaring Meg Pinot Noir Central Otago (£17.49, or £14.99 each for two, 14 per cent, Majestic) Roaring Meg was a bar owner and good time girl in the days of the Bendigo gold rush. The wine that bears her name is suitably juicy and appealing, with supple red and black fruits and a touch of sweet oak.

2006 Kumeu River Estate Chardonnay Auckland (£15.50, 13.5 per cent, The Wine Society; Boxford Wine Company, 01787 210187) Michael Brajkovich’s range of outstanding chardonnays is among the best in the New World. This elegant oaked white is like a Kiwi take on a Puligny-Montrachet. It is really that good.

2008 Man o’War Syrah Waiheke Island (£16.99, 14 per cent, Caviste, 01256 770397) I can’t remember the last time I was as impressed by a syrah from outside the Rhône Valley. This comes from Waiheke Island and shows savoury, pepper spice notes, oodles of blackberry fruit and smooth tannins.

First published in The Times