The struggling sports retailer has been trying to stage a fight back after it came close to going into administration earlier in the year.
But the latest gloomy figures have been partly fuelled by a lack of stock as some suppliers have snubbed the firm during its financial problems.
The chain’s like-for-like sales decline – which takes into account store closures – was 29 per cent.
A slight rally ended in the first three weeks of December when sales tumbled 32 per cent.
JJB made a loss of £42.9m in the first half of the year with tough competition from JD Sports and Sports Direct taking its toll.
The company is hoping that its sale on 26 December will help to fuel a recovery.
JJB raised £100m from shareholders in a rights issue earlier this year in a bid to reduce its huge debt.
The Wigan-based group said that stock levels had improved but admitted the trading environment “will remain difficult”. The levels will not return to where they want them until the first quarter of 2010.
In the interim management statement, JJB said : “We continue to be cautious about Christmas and New Year and expect that trading within the current environment will remain difficult.”
Analysts warned tough times remain ahead. “The market is anticipating [profit] upgrades and so performances will need to be exceptional,” said Shore Capital analyst Kate Calvert of Christmas trading.