President Barack Obama, seeking to quell an election-year firestorm, will unveil a plan on Friday to accommodate religious organizations outraged by a new rule that would require health insurance coverage of contraceptives, sources close to the matter said.

Obama will speak at the White House at 12:15 p.m. EST (1715 GMT) to announce a compromise on the birth-control issue, which has sparked an outcry from Catholic Church leaders, Republicans and other social conservatives who denounce the rule as an attack on religious freedom.

The policy shift is aimed at defusing the controversy and preventing it from becoming a liability for Obama's re-election campaign, but it was unlikely to assuage all of the concerns of church leaders.

The proposal will aim to show flexibility toward religious organizations, but will preserve the central White House goal of ensuring that women employees of religious-affiliated institutions, including schools and hospitals, receive full coverage of contraceptives in health insurances plans.

The administration has been looking at several state laws, including those that let religious employers opt out of covering birth control in their insurance packages, so long as they refer women to a provider that will offer the benefit at low cost.

But Catholic leaders have already said they oppose that option, arguing that referring women to low-cost contraception is as immoral as distributing the drugs and devices first-hand.

The regulation at the centre of the controversy requires religious-affiliated groups such as charities, hospitals and universities, but not churches themselves, to provide employees coverage for birth control as other health insurance providers must do. The Catholic Church opposes most methods of birth control.

Polls indicate a majority of Americans and Catholics support the rule. A Public Religion Research Institute poll taken last week found 55 percent of Americans want employers to provide healthcare plans that cover contraception and birth control, including nearly six in 10 Catholics.

So far, the church's protests have focused mainly on their fear that the new requirement abridges their religious freedom.

(Additional reporting by Susan Heavey and Vicki Allen; Editing by Vicki Allen, Ross Colvin and Jackie Frank)