Any increase would mean the promise by owner Centrica going up in smoke after just four months and was branded a "slap in the face for consumers".
The company, which supplies 12 million homes, declined to comment,
It was reported yesterday that the rise could come as early as October just as temperatures start to plunge, with a hike of up to 10%, taking a typical "duel fuel" bill to a record £1474.
It comes amid speculation that other so-called Big Six suppliers - SSE, EDF, ScottishPower, E.ON and npower - are also preparing to raise pricess, despite soaring profits following the freezing weather earlier this year.
The increases would mean more pain for consumers already under pressure as wage rises continue to lag behind inflation. British Gas previously hiked tariffs by 6% last December, a rise that helped Centrica cash in handsomely on the misery of householders over a bitterly cold period, as gas consumption rose 18% in the first four months of this year compared to 2012. The company said in May that because of the economic pressures facing many customers, the board had decided that any benefit from the exceptionally cold weather would be used to maintain "price competitiveness".
But by July Centrica was already hinting at further price rises, saying a new duty to pay for energy efficiency measures in customers' homes had hit earnings. A British Gas spokeswoman said: "We don't comment on price speculation."