Mrs Fletcher said she still expected the event to sell out.
"We are delighted with demand for this perennial event."
The event is set in 11 boutique vineyards, offering festival-goers a unique opportunity to taste wines from both current and past vintages.
Each vineyard will partner with a top restaurant or caterer and performance artists such as The Warratahs.
Alana Estate, Ata Rangi, Escarpment, Dry River, Margrain Vineyard, Martinborough Vineyard, Muirlea Rise, Palliser Estate, Te Kairanga, Tirohana Estate and Vynfields are taking part in this year's event.
Mrs Fletcher said the 2013 festival's line-up was designed to appeal to the most discerning of wine connoisseurs.
"It's a showcase of the very best that our region has to offer, and a unique opportunity to taste the wines that have taken Martinborough to the world."
Local cafes and restaurants offering food at the festival include Cafe Medici, Wharekauhau Country Estate, Tirohana Estate restaurant, Bar Salute and the Vineyard Cafe.