Sky Television subscribers will soon be able to watch programmes on their computers at the same time they are shown on TV, the company says.

The online television service, iSky, will be delivered by internet service provider Orcon, which is building a nationwide content-delivery network.

Only one online login will be given per Sky subscription and only one computer will be able to access the content at any time.

This means that one family member could be viewing one of the sports channels on the TV, while another watches iSky content elsewhere.

The service will be available before the end of the year, Sky says.

Sky has not yet announced how many channels will be streamed online or which channels those will be, but movies on demand, the pay view channel now available on Sky, will be available on iSky - also for a fee.

Pay movies over the next month range from Alice in Wonderland toDate Night and Zombieland.

Sky TV's director of communications, Tony O'Brien, said the feature would work in a similar manner to how it does on MySky.

The customer would have access to the movie for the specified time period and be allowed to view it as many times as desired, after which it would be deleted from the customer's iSky account.

O'Brien said it was important for Sky to be able to provide customers with live online content.

"It's combining the role Sky has as a content aggregator with a content delivery network, and a state-of-the-art website.

"The system is optimised for viewing long-form video content.

"iSky users will be able to access a selection of online content that is streamed directly to personal computers, giving them portability and individuality." O'Brien said iSky users would not be able to save programmes they viewed on iSky like MySky customers can because of restrictions imposed by content suppliers and production studios concerned about copyright breaches.

Orcon head of wholesale Charlie Boyd said iSky would bring content closer to the customer while reducing the cost of accessing it.

Orcon will work with Alcatel-Lucent's next-generation digital media delivery platform Velocix and with Kordia's nationwide data network.

The technology will enable Orconto build a network that distributes high-quality internet-based video content.

"As streaming TV websites and video-on-demand grow in popularity, the amount of online video watched by broadband users is growing at an incredible rate," Boyd said. "We can offer content providers a solution that meets their specific requirements."