And the Belfast Telegraph can reveal that the party is facing the loss of one fifth of its sitting Assembly party in what may be a significant indicator of internal problems.

Former Sinn Fein MLA John Kelly, a founder of the Provisional IRA, and Brendan Hughes, a former Maze hunger strike leader, claimed that threats were made towards republicans "who seek a wider debate on the policing matter".

In a published letter, the two men allege that a number of people have been warned by Sinn Fein "that they must not attend independent meetings organised by republicans around the policing issue".

They also state that the Sinn Fein leadership is afraid of facing the possibility of an electoral challenge from within republicanism.

"It is not the threat of physical attack that Sinn Fein leaders fear. This is evident from the way they continue to go about their daily lives.

"It is the possibility of republicans fed up with Sinn Fein lies and deceit deciding to mount an electoral challenge that send shudders of anxiety through the leadership circles," the letter to the Irish News read.

It continued: "We are concerned that in a bid to stifle wider discussion within the republican community, Sinn Fein is pursuing a strategy of threat against dissenting voices.

"They are disguising their own menace by attributing violent intent to those voices. Such voices are healthy in a republicanism unafraid of critical self-examination."

The claims have been dismissed by Sinn Fein. A party spokesman told the Belfast Telegraph: "This is total nonsense. It has no basis in fact or reality."

Five members of the party's 24 in the Assembly are off the ballot, with another expected to stand down before the elections on March 7. This may not translate into a loss of seats but it may represent a sign of discontent within the party.

Among the members who will not be seeking re-election are Geraldine Dougan, MLA for Mid-Ulster, who stated that her decision was for personal reasons, but who has also been quoted as saying that she has concerns about policing.

North Belfast MLA Kathy Stanton will also not be seeking re-election. Two others - Davy Hyland and Pat O'Rawe - were both de-selected by the party, although their situation is not fully resolved. Sinn Fein is also without Michael Ferguson, who died last autumn.

In 2003 three members of the Sinn Fein Assembly party also left before that year's elections. They included Mid-Ulster Assemblyman Mr Kelly, who resigned from Sinn Fein over differences with the leadership, Mick Murphy, who was de-selected in South Down, and Pat McNamee who stepped down in Newry and Armagh because of ill-health