The Health and Safety Executive has asked for extra time to consider calling-in the Lambeth Borough Council's decision to approve a revamped 5,000-seat stand and 168 bedroom hotel at the Oval in January.
The HSE was originally given three weeks to review the approval. It is now expected to reveal its decision to the Government Office for London by 5 March.
The office has served an order blocking the application until the HSE makes up its mind on the likelihood of safety fearsfrom the nearby gasholder.
A previous application for the project had been refused by the council in October last year following HSE fears that it could cause an explosion at the gas holders.
But joint developers Surrey County Cricket Club and Arora International submitted a new application including a report from consultants BT&P and Hyder which said the chances of a major gas explosion that would endanger those in the ground was so low as to be ruled out.