Worcester Warriors will be suspended from all competitions unless club chiefs provide the Rugby Football Union with safety certification to stage matches at Sixway Stadium by midday on Friday.
English rugby chiefs have written to Gallagher Premiership club, demanding proof of safety certificates to allow Warriors matches to continue.
Worcester's Premiership match against Exeter at Sixways on Sunday is now in doubt, unless Warriors owners produce the relevant documents by midday tomorrow.
In a statement, Worcester said, "Our staff have been working hard this week to ensure that we comply with the requirements for a General Safety Certificate and we will continue to do so on Friday morning to ensure that we are fully compliant.
The RFU has demanded evidence of council safety certificates as well as medical cover.
Worcester owners Colin Goldring and Jason Whittingham have claimed to have agreed terms on the club's sale, but rugby's authorities remain yet to be convinced with players and staff still in limbo.
In a statement the Rugby Football Union said: "The RFU has written to Worcester Warriors to confirm they will be immediately suspended from all competitions, including the Gallagher Premiership, Allianz Premier 15s and Allianz Cup if assurances as to the ability to safely hold matches at Sixways Stadium are not provided by 12 noon on 16 September.
They continue: "This includes evidence that the local authority has issued a General Safety Certificate, and written confirmation of medical provision.
"Any suspension may be lifted once the club has more security of funding and is able to evidence its ability to hold matches safely.
"The RFU, PRL and DCMS has been seeking assurances from the Worcester Warriors owners regarding funding and potential new ownership proposals for several weeks."
Worcester Warriors also issued a statement and said: "Worcester Warriors understand the position of the RFU, PRL and Department for Digital, Culture Media and Sport concerning the requirements for staging this weekend’s Allianz Cup and Gallagher Premiership matches at Sixways.
They continued: "Our staff have been working hard this week to ensure that we comply with the requirements for a General Safety Certificate and we will continue to do so on Friday morning to ensure that we are fully compliant.
"We, and the potential new owners of the club, are also aware of the serious consequences that may follow if the club is suspended from playing any competitive rugby.
"The best solution to avoid such a sanction is to ensure that heads of terms on the agreement with the new owners are signed as quickly as possible. Work continues this evening to that end.
The Warriors were forced to deny being forced into an administration earlier on Thursday, after the Department of Digital, Culture, Media and Sport staff sent out a statement in error.
An email declaring Worcester had fallen into administration was sent out to supporters, with Warriors quickly insisting the statement was a mistake.
The DCMS had prepared the email in case of the club entering administration, but a draft was accidentally sent.
A statement from Worcester Warriors read: "Worcester are aware of a letter that is in circulation from the Department of Digital, Culture, Media and Sport claiming that the owners have put the club into administration. This is NOT true.
"The statement was sent out in error by DCMS who have apologised for their mistake and the distress and anxiety it has caused to our staff and suppliers at what is already an extremely stressful time.
The DCMS is understood to be looking into how the error occurred, and is continuing to work with Worcester, the Rugby Football Union and Premiership Rugby on options around their survival.