The Office of Fair Trading has recommended that BSkyB's acquisition of a 17.9% stake in rival broadcaster ITV be referred to the Competition Commission.
Trade and Industry Secretary Alistair Darling must decide whether to act on the OFT's recommendation by May 26.
OFT chief executive John Fingleton said: "This partial ownership link between two key players raises significant competition concerns. Sky's shareholding means that ITV is no longer fully independent."
Media regulator Ofcom added that BSkyB's acquisition of the stake for £940 million last November raised public interest concerns over the "sufficient plurality of news provision" in the UK.
Mr Darling will also consider Ofcom's advice before making any recommendation to the Competition Commission.
ITV shares rose by more than 1% as analysts speculated that ITV could become a takeover target if Sky is forced to sell its shareholding.
The OFT launched an investigation into BSkyB's purchase of the stake in January. It said that "a relevant merger situation" had been created which could substantially lessen competition in the UK market.
It added that BSkyB had not offered "clear cut remedies sufficient to resolve competition concerns".
Mr Fingleton added: "This may alter the future competitive landscape, especially as we approach digital switchover.
"Given the high stakes for tens of millions of UK consumers, we believe these risks to competition merit further examination."
