The cable operator claimed it had no plans to change its relationship with Saatchi & Saatchi, which creates the bulk of Telewest's advertising, but confirmed it was reviewing the way it works with agencies.
Telewest, which this week announced plans for further job cuts and a restructure of its operations, currently spends £6 million on advertising.
Its also uses agencies including Carlson, DraftWorldwide London and Heresy to handle its below-the-line and digital activity.
Agency sources said Telewest was touring agencies to get a view of the market before calling a review.
A Telewest spokeswoman said: "We are still working with Saatchis and have no plans to change this. Basically, we are always reviewing the way we work with agencies."
Telewest is currently addressing problems that have led to debts of more than £3 billion. Its new chief executive, Charles Burdick, replaced the ousted Adam Singer last month. Philip Jansen, Telewest's consumer managing director, also left the company recently.
The company is talking with creditors about a restructure that could lead to a merger with its rival ntl next year. The deal would see existing shareholders, including Liberty Media, reducing their equity.
Telewest currently has 1.8 million UK customers. The bulk of its adspend supports its cable service, broadband service and telecommunications offers.
Earlier this year, Telewest was rapped by the ASA for an ad through Saatchis for its Talk Unlimited service that used the line: "Stay off that bloody phone."