Sinn Fein's finance spokesman Pearse Doherty has insisted Daithi McKay acted alone in relation to relation to allegations that he coached a witness at the Northern Ireland's finance committee.

Mr McKay resigned as an Assembly member last week after claims that he was communicating on Twitter with loyalist blogger Jamie Bryson ahead of his appearance before the committee's inquiry into the Nama loans deal. The former North Antrim MLA has been suspended by Sinn Féin. Sinn Féin worker Thomas O'Hara has also been suspended by the party.

It is alleged that Mr Bryson was allowed claim to the finance committee last September that former first minister Peter Robinson was to gain financially over the £1.2 billion purchase of Nama's Northern Ireland portfolio by American investment giant Cerberus. Mr Robinson dismissed that claim as "scurrilous and ill-founded

Mr Doherty said Mr McKay was right to resign his position as an MLA for failing to live up to the standards of the party.

He said: "I am the finance spokesperson but I would imagine if this was something known within Sinn Fein I would know.

“Daithi McKay acted alone, he has made that clear and he has suffered the consequences for that and it was the wrong thing for him to do at that time but he has done the right thing in stepping aside.”

All senior members of Sinn Fein have insisted his party had no knowledge of the alleged contact between Mr McKay and Mr Byrson.

Mr Doherty said he was confident the Northern Ireland Minister for Finance Martin O’Muilleoir was not involved.

The Donegal TD said all association to the Minister was "innuendo" and not "hard evidence".Asked if Mr O'Mulleoir should stand aside if found to be involved, Mr Doherty said: "I would be shocked but of course he would. I would be shocked."