Five, the terrestrial television channel, is expected to make about a third of its workforce redundant this week.
A source close to the company said that around 100 of the 350 staff would lose their jobs as part of a restructuring of the business to be announced on Thursday. Earlier, ITV is expected to axe up to 500 jobs when it announces its annual results.
A senior media banker said: "Five management has approved the budget for the next financial year and it will involve a very significant headcount reduction. ITV is also having another meaningful [jobs] haircut."
A Five spokesman confirmed that the company would be "speaking to staff next week".
Broadcasters are suffering from a big downturn in advertising revenues, estimated to have fallen by as much as 20 per cent over the past year.
Last week, it was reported that ITV had drawn up plans to create a major broadcasting player to rival the BBC. This would involve the merger of ITV, Channel 4 and Five, in a move industry experts concluded could save the broadcasters an annual £200m through sharing administration costs.
A source close to Five said that ITV had not contacted the company about the idea, adding that Bertelsmann, the German group that ultimately owns Five, whose CEO is Dawn Airey, would not support such a merger.
This runs contrary to speculation earlier this year that Bertelsmann is considering a tilt at ITV. Leading investment banks, including UBS and Goldman Sachs, are understood to have contacted FTSE 250 listed ITV over a possible bid defence.
Lazard is ITV's usual adviser. The bank is currently overseeing the sale of Friends Reunited, the social networking website, which ITV has owned since 2005. Analysts fear that the sale would raise about £40m, less than a quarter of the £175m which ITV paid for the business.
ITV is also considering the sale of SDN, which leases space on Freeview The business cost £134m in 2005, but is expected to fetch at least £70m more, if ITV goes ahead with the move.
Broadcasters are due to hand in ideas for the future of UK television as part of the Government's Digital. Britain review by 12 March. The review has already suggested that BBC Worldwide and Channel 4 could share certain functions to save cash in an increasingly pressured media market.
The review has led to an Office of Fair Trading examination of ownership in the local newspaper market, which is suffering from a severe downturn. However, there are also stringent competition rules, which are preventing potentially market-saving consolidation.Reuse content