Analysts said the portal would make it easier for retailers, which may not have previously considered digital TV as a viable sales channel, to launch iTV services.
The integrated portal, accessible through the Sky Active iTV service, will enable any UK retailer to offer its products to Sky Digital's 6 million subscribers, who will be able to watch a Sky channel while browsing the virtual shelves.
Tobin Ireland, commercial director at Sky Interactive, said the portal opens the door to retailers of any size to sell products on Sky Active, which is accessed by about 2.4 million users a week.
"There has always been a demand for shopping services on TV, now we have a solution that will give the breadth and depth of product range that retailers are looking for and enhance the overall retail offer," he said.
Chris Tant, managing analyst at research firm Datamonitor, said the portal, which will be launched in conjunction with e-commerce platform provider Altura International, would allow retailers to capitalise on Sky's brand.
"In general iTV only really works for large, trusted brands but this will open it up beyond that for smaller and more specialist retailers in a cost-effective manner," he said. "You can argue that it does not matter whether the consumer has heard of the retailer, because Sky is a trusted brand in itself."
The portal will initially be branded "Christmas Gifts", have a single checkout for all purchases and support the use of T-vouchers - online vouchers for use on interactive TV services.
"The introduction of T-vouchers will allow retailers to use conventional direct marketing strategies and promote specific products effectively," Ireland said.