The Home Office confirmed that tribunal hearings dealing with such cases could be adjourned until the overhaul of policy - which could affect 1,000 people immediately - is finished.
The review, which a spokesman said could take "some time", will determine whether the immigration entry criteria could be made the same for all couples, married or unmarried, heterosexual or gay. At present individuals can join their partners only if they are married or engaged.
Ms Widdecombe said yesterday she opposed any relaxation of the immigration laws for common law or single sex relationships, which would "open up the floodgates for abuse" of the system.
She said the previous government had tightened the immigration system to prevent people coming to the UK fraudulently. There was no need for a review and any relaxation of the rules "would be very, very easily abused", she said.
She added: "The system makes it clear you must have a valid and subsistent marriage. If you allow people to come in on the basis that they have a same-sex relationship you have no real means of testing it."
Last night the gay rights group Stonewall said it knew of 500 gay couples who want to live together in Britain and would be allowed to if the law was changed.
A Stonewall spokesman said: "We think everybody should be treated equally before the law. We think it's wrong that 500 couples have no right to live together in the same country."
"Jack Straw has made a commitment," he said. "We are quite confident that he will deal with that, but we do not know on what terms."
A Home Office spokesman said: "The Home Secretary gave a commitment in opposition to review the position of homosexual and common law partners applying for entry to the UK."Reuse content