Ofcom is to launch an investigation into the way Sky supplies its subscription sport channels to rival broadcasters, it has been reported.
The communications regulator is acting upon a complaint from Sky's major competitor BT, which is entering the sports pay-TV market this summer.
BT has raised issue with the terms upon which Sky is prepared to offer Sky Sports 1 and Sky Sports 2 for BT TV customers via YouView.
According to the firm, Sky is refusing to provide access to its sports content unless BT reciprocates by enabling Sky customers to watch BT Sport.
BT has claimed that this is an abuse of Sky's market dominance, reports the BBC.
"We are pleased Ofcom has decided to open an investigation as we believe Sky has behaved in an unreasonable and discriminatory manner," BT said in a statement.
"This is because they have refused to provide Sky Sports 1 and 2 to BT on YouView on fair terms whilst providing them to other pay-TV retailers such as TalkTalk."
However Sky has dismissed BT's complaint, describing it as being "entirely without merit". The firm said it "looks forward to engaging constructively with Ofcom".
The two rivals have been exchanging heated words ever since BT secured the live rights to 38 Premier League games per season earlier this year.
Matches will be broadcast on the firm's two branded channels - BT Sport 1 and BT Sport 2 - and on ESPN, which is now under the BT banner.
Sky will continue to show the lion's share of matches - 116 per season from 2013-14 - however BT is making its coverage available for free to its broadband subscribers.
In response, Sky has launched a number of new broadband deals, offering discounts on bundles including internet services and Sky Sports.