Gay partners are to be given the same rights as married couples under plans to be unveiled by ministers on Monday.

Homosexual partners will secure the same entitlements in areas such as inheritance, property and pensions.

In a consultation paper ministers will propose a system where same sex couples can sign a partnership register giving them the same legal rights as their married counterparts.

Under the scheme couples will have to sign an official partnership document - although the government will stress the move does not amount to gay marriage.

They will also be able to dissolve the agreement in a move similar to a divorce settlement.

The gay rights lobby has long argued that denying homosexuals the right to next of kin status leaves many couples in limbo when one partner falls ill.

It also argues that it is unjust to levy inheritance tax on a property when it transfers to a gay person following the death of a lifelong person.

Homosexual lobby group Stonewall welcomed the move and urged the government to act quickly.

"Hundreds of thousands of gay people are in stable, long-term relationships but still don't have the same rights as many others," said Stonewall's Ben Summerskill.

"It's not just social status that matters, like the right to visit each other in hospital, but the right to share a partner's pension, for example - which is something available to every heterosexual.''

"We hope that parliamentary time will be made in the next session for the Bill. Every day's delay is a very real human tragedy for individuals all around the country."

But critics say the government has failed to address the issue of unmarried heterosexual couples - who will still be denied the same right as married partners.

The Lib Dems welcomed the gay partnerships moved but questioned why it would not apply to straight couples.

"This step is long overdue. Liberal Democrats welcome the changes that will be made to inheritance and next of kin rights and pensions sharing for samesex couples," said Evan Harris.

"But it is typical that the government has only done the bare minimum. The decision to exclude opposite sex couples from claiming the rights conferredby civil partnerships will be a bitter disappointment to hundreds of thousands of heterosexual unmarried couples.

"Currently the government treat them as married when cutting their benefits, but ministers are clearly refusing to reciprocate when it comes to pensionsharing. These couples are under pressure to marry for financial reasons.

"Civil partnership registration schemes established in London and Liverpool are for same sex and opposite sex couples. The government should follow suitand legislate to give all unmarried couples the same rights."