GERRY Adams ignored the mounting pressure on him over the murder of Jean McConville as he called yesterday for an international process to deal with the past in Northern Ireland.
Two dead IRA members, Dolours Price and Brendan Hughes, claimed before their deaths that Mr Adams ordered the murder of Ms McConville, a Belfast mother of 10, when he was a Provo commander.
Mr Adams denies being a member of the IRA and says the late Ms Price and the late Mr Hughes were lying.
Mr Shatter said others would "ultimately judge" whether Mr Adams was telling the truth.
"I find the approach of Gerry Adams and Sinn Fein difficult to accept," he said.
"There is an enormous credibility gap around Gerry Adams's approach to this; Sinn Fein's approach to this," he said on RTE's 'The Week In Politics'.
Sinn Fein finance spokesman Pearse Doherty said the documentary on the Disappeared was a "harrowing programme".
But Mr Adams failed to address the growing questions for him personally as he called for an independent international process to deal with the past in Northern Ireland.
"The past cannot be an obstacle to dealing with the present or a pretext for refusing to build a new future. While republicans recognise the difficulties confronting all of us in dealing with this issue we are not daunted by it. Nor should anyone be," he said.
On Remembrance Sunday, Mr Adams said efforts to deal with the North's past and seek truth and reconciliation have not made the progress they should have since the Good Friday Agreement.
"Sinn Fein has proposed an independent international- based process to deal with the past. The fact is that none of the participants to the conflict can be responsible for creating such a process," he said.
"The British government has refused, so far, to agree on any mechanism that can deal with this issue and the Irish Government has made no real effort to establish a viable truth recovery process. This is not acceptable," Mr Adams added.
He also said that claims he protected a paedophile were "vicious, obscene and offensive".
Northern Ireland Health Minister Edwin Poots made the allegation against the Sinn Fein president during an assembly debate last week.
Mr Adams has been accused of withholding information about his niece's sexual abuse by his brother, Liam Adams, who was found guilty of rape last month.
The Sinn Fein leader told BBC Radio Ulster's 'Sunday Sequence' programme he "tries not to rise" to the comments. "Edwin Poots is more to be pitied than to be scorned," he said.
Mr Poots has accused Mr Adams of not reporting his brother to the authorities. The matter is being investigated by the Northern Ireland attorney general.
"Some of the statements (by witnesses in the documentary) were very, very definitive. They were made by people who had no reason to lie about the matter. . . It's a very, very serious matter. I can imagine what would happen if allegations of that sort were made against the leader of any other political party in the Dail – there would be screams from all sides for a debate," he said.
"I would agree with the demand for the debate."