Sinn Fein could be excluded from the review of the Northern Ireland peace process.

Downing Street signalled its support on Wednesday to comments by Northern Ireland secretary Paul Murphy that Sinn Fein could be expelled.

The independent monitoring commission is carrying out an investigation into the alleged abduction of a leading republican and if Sinn Fein is criticised, the party will be expelled.

"Paul Murphy's words speak for themselves," said the official spokesman.

"The prime minister's views on paramilitary activity were made crystal clear. The government does have concerns regarding paramilitary activity."

Murphy himself highlighted the importance of the commission's role. 

"The commission does have an extremely important role to play not just in this but in the vital issue of paramilitary activity," he told MPs.

The comments come ahead of fresh talks with the Irish government to decide a full response to the current crisis.

Issues were brought to a head after a Republican opponent of Sinn Fein was abducted - which was blamed by Northern Ireland's chief constable on the IRA.

The IRA leadership has denied it authorised the attempted kidnapping.

As a result, Ulster Unionist leader David Trimble demanded that the government exclude Sinn Fein from the review which has now begun.

Sinn Fein responded to the current problems by challenging Murphy to a public debate about paramilitary activity.

"The politics of exclusion failed us in the past and they will fail again if tried in the future," warned Sinn Fein national chairman Mitchel McLaughlin.

"I would challenge Paul Murphy to a public debate on the issues of paramilitarism and the politics of exclusion. We tried to have this discussion within the parameters of the review but the British government ran away from the debate and cancelled a planned plenary meeting on these important matters."