Fans of popular drama series such as Billions and Scandal may find themselves frozen out of their cable boxes on Thursday - if local pay-TV operators fail to strike a deal with distributor Fox Networks Group (FNG).

More than 20 channels, including popular ones like National Geographic Channel, Fox and Star World, could be yanked off StarHub's pay-TV service this week unless a new contract is inked between StarHub and FNG. The current deal does not include sports channels such as Fox Sports and Star Cricket, which come under a separate deal.

Likewise, Singtel's deal with Fox ends next month. They too have not struck a new deal and also face a possible blackout.

The Sunday Times understands that negotiations have gone on for months, with cost a sticking point. Fox's unwillingness to entertain a joint bid from both operators is believed to be another reason for the impasse.

Mr Howie Lau, StarHub's chief marketing officer, told The Sunday Times: "The ongoing renewal negotiations with FNG have been very challenging and protracted but we are still working hard to come to an agreement which creates value for our customers, FNG and ourselves. We thank our customers for their patience and understanding."

Singtel declined to comment.

FNG Singapore general manager Fion Yeo said the group is hopeful that a deal could be reached.

Viewers are, however, upset at the prospect of a blackout.

Communications consultant Gregory Cheong, 27, a fan of Fox's movie channels, said: "It's disheartening that we're always having to concern ourselves with what we're able to watch even though we've signed up for a package."

Added training manager Viola Balakrishnan, 49, who watches Fox Movies Premium: "It is unfortunate that we might lose the channels. I spend a lot of time with my family watching movies on Fox Movies Premium. But I agree with StarHub on principle that if the prices are astronomically high, we should not just adhere."

This is not the first time that Fox channels have been taken off air. In June, StarHub went dark on five Fox channels after no agreement was reached for a renewal.

A Media Development Authority (MDA) spokesman said: "The continuation or cessation of channels ultimately depends on commercial considerations such as viewership and costs, which MDA does not intervene in."

Should transmission of Fox channels cease on pay-TV platforms, consumers can terminate their contracts without penalty.

The MDA introduced a series of changes to consumer protection in pay-TV in March, one of which allows consumers to terminate their contracts if there are changes to pricing or programming. However, this new ruling covers only subscription packages signed after April 30.

For those who signed their contracts before April 30, corporate lawyer Krishna Ramachandra, managing director at Duane Morris & Selvam LLP, said they would still have recourse through the Consumer Protection (Fair Trading) Act, adding that there is less legal uncertainty following MDA's changes.

The latest development comes amid a climate of ever-increasing content cost, one which has led to protracted talks between rights holders and broadcasters.

The rising content costs saw national broadcaster Mediacorp strike a deal to show the recent Olympics live only a day before the opening ceremony.

The situation is exacerbated by the fact that pay-TV operators here are facing declining subscription numbers. There is also competition from alternative viewing platforms and streaming services. This includes Netflix, which allows users to bypass commercials.