A row between two of the world's biggest media players has intensified this week, with Rupert Murdoch's News Corp saying it will hold Jean-Marie Messier's Vivendi Universal to an agreement to merge their Italian pay-TV businesses.

According to UK paper The Financial Times, News Corp is expected to go to court to force the completion of the deal to merge Vivendi's Telepiu and Stream, a 50-50 joint venture between News Corp and Telecom Italia.

News Corp has told Vivendi that pulling out would be contrary to their original agreement and said the French-based group's financial constraints were "not valid reasons" to abandon the deal.

The plan was announced a year ago as a way of keeping both loss-making satellite operators afloat.

Mr Murdoch told investors earlier this week that he would sue Vivendi if it tried to renege on the deal. "If Vivendi doesn't go through with it, we'll sue them," reported The Financial Times. "And Stream will stay in business as a very active competitor. We can continue to fund it and so can our partner Telecom Italia."

Vivendi on Wednesday said it had given up on the $420m Telepiu`-Stream deal after Italian regulators set 10 contractual conditions before permitting the creation of a satellite monopoly in the country.

Canal Plus, Vivendi's pay-TV arm, yesterday said Mr Murdoch would have no grounds for suing. It said there was no break-up fee.