George Robertson, Martin Bell and Mike Whitlam debate the government's delay on BBC Radio 4's Today (1)

Mr Robertson told an international conference on landmine elimination that ministers were actively looking at ways of pushing through the necessary legislation before MPs break for summer recess.

Princess Diana had been a leading figure in the campaign to ban landmines before her death last year.

Mr Robertson told the conference organised by the British Red Cross: "We are looking at this matter with some degree of urgency and we have not ruled out taking more rapid action than was previously assumed."

Mr Robertson has come under growing pressure after it was disclosed that the legislation to ratify the Ottawa Convention was unlikely to be put to Parliament in the current session.

Mr Robertson told the conference ratifying the convention remained one of the government's "key priorities."

"We are looking very carefully at how we could get the ratification through as quickly as possible," he said.

Defence Secretary George Robertson says the delay is due to lack of time

He went on to pay tribute to the role played by Princess Diana in generating the international will to securing the Ottawa Convention.

He said: "She contributed enormously to bringing the world's attention to the devastating effects of anti-personnel landmines and thereby to the success of the Ottawa process

"A momentum has been generated and we must do all we can to ensure that it is sustained."

Earlier, Mr Robertson told BBC Radio 4's Today programme, the issue had been held up by a congested parliamentary session, made worse by the pressures of Northern Ireland.

He stressed the government was ahead in its programme to get rid of its own stocks, with 450,000 anti-personnel landmines, almost half of the total stocks, having been destroyed.

He said: "We signed the treaty and unilaterally we banned the production, export, import and transfer of anti-personnel landmines and declared a moratorium on their use."

Bell: Hold special session on Diana anniversary

Mr Robertson came under fire from former BBC war correspondent Martin Bell. The independent MP demanded ratification by the end of parliament or at the very latest by the first anniversary of the death of Princess Diana on August 31.

Mr Bell even called for a special reconvening of parliament on the anniversary of Diana's death to ratify the treaty.

The Director General of the British Red Cross, Mike Whitlam, said he believed there would be no opposition to ratifying the treaty in parliament.

George Robertson, Martin Bell and Mike Whitlam debate the government's delay on BBC Radio 4's Today programme (2)

He said: "We are saddened that the government has not actually got to the point of ratification."

He told the Today programme the UK Government was central to getting other countries to sign up to the ban.

He added: "Every day that we delay this process, every day they [landmines] continue to be made means more women, more children are still being killed and for the sake of half a day in parliament, I think people's lives are worth that."