A new study of militaries around the world has found that changing policy to allow gay soldiers to serve does not cause disruption.

The US is currently moving toward lifting the ban on gays and lesbians serving openly in the military but opponents contend it will cause too much disruption at time of two wars.

The Palm Center report is due to be released tomorrow and according to the New York Times, it will conclude that in other militaries around the world, allowing gay personnel to serve openly did not undermine morale or cause mass resignations.

It will say there were “no instances of increased harassment” as a result of lifting bans in any of the countries studied, which included the UK, Canada and Australia,

The report was principally authored by Nathaniel Frank, who wrote the book Unfriendly Fire: How the Gay Ban Undermines the Military and Weakens America.

President Barack Obama supports repeal, along with a number of high-ranking military and civilian leaders. This month, a Senate Armed Services Committee began hearings on how the law can be changed.

The report found that all countries studied had lifted their bans quickly, rather than gradually, and none had felt the need for “separate but equal” measures such as separate washing facilities, which opponents of lifting the US ban claim will be necessary.

The New York Times said: “On implementation, the study said that most countries made the change swiftly, within a matter of months and with what it termed little disruption to the armed services. Mr Frank said the study did not look at what happened if the change was implemented gradually because, he said, ‘I don’t think any of the militaries tried it.’”

Pentagon leaders have said they will need at least a year to change the policy.

Defence secretary Robert Gates has begun a year-long review on implementing the change and Admiral Mike Mullen, current chairman of the Joint Chiefs of Staff, told the hearings he believed removing the ban was the right thing to do.

Public support has steadily grown in favour of repeal in recent years. Polls generally show just over half of US citizens support removing the ban.

In late January, just after President Obama announced his intention to repeal the 1993 law, John McCain, the 2008 Republican presidential candidate, said he believed it would be a “mistake” to repeal it in the middle of two foreign wars.