US defence secretary Robert Gates is expected to confirm today (Tuesday) Pentagon plans to begin rolling back the ban on gays and lesbians serving openly in the military.

A US defence official told AFP that the review would look at what steps could be taken towards repeal.

The official said: “He [Gates] will appoint a very senior Pentagon civilian official and a very senior uniformed officer to oversee a year-long review of steps we need to take in preparation for the eventual repeal of Don’t Ask, Don’t Tell.”

Gates and the chairman of the Joint Chiefs of Staff Adm Mike Mullen are expected to appear before the Senate Armed Services Committee today.

However, they may warn it will take years to fully change the policy.

Opponents argue that the current wars in Iraq and Afghanistan mean now is not the time for the military to face further strain. They also believe lifting the ban could harm cohesion and dissuade new recruits from joining the armed forces.

The review would have to look at issues such as benefits for gay servicemembers’ partners and whether they will share living quarters with heterosexual troops.

Gates said last year he wanted to make the law more “humane”. He is expected to suggest removing the provision for gays and lesbians to be outed by a third party and raising the bar of evidence needed to fire someone for homosexuality.

Last week, President Barack Obama promised he would work to repeal the 1993 law this year.

He said in his State of the Union address: “This year, I will work with Congress and our military to finally repeal the law that denies gay Americans the right to serve the country they love because of who they are. It’s the right thing to do.”

The law was implemented by President Bill Clinton as a compromise on an outright ban on gay troops. It means gays and lesbians can serve as long as they do not engage in homosexual behaviour or reveal their sexual orientation to their superiors.

The law is often known as Don’t Ask, Don’t Tell, as senior officers are barred from asking servicemembers about their sexuality. However, they can be outed by another person.

Since the law came into force, an estimated 13,000 servicemembers have been dismissed.