Mairtin O Muilleoir says he was unaware of colleague's contact with probe witness

Stormont's Finance Minister has insisted he knew nothing of a party colleague's controversial contact with a witness to an inquiry into Northern Ireland's largest ever property deal.

Mairtin O Muilleoir said those seeking to link him to the controversy that forced the resignation of Daithi McKay, the former Sinn Fein chairman of the Assembly's Finance committee, were indulging in "petty party politicking".

Mr McKay apologised and quit as an Assembly member last week after private Twitter messages published in the press showed him communicating 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 Fein.

Sinn Fein worker Thomas O'Hara has also been suspended by the party.

He was also accused of communicating with Mr Bryson about his evidence before he made explosive claims to the finance committee about the efforts of Ireland's bank for bad loans to dispose of its Northern Ireland portfolio to US investors.

Mr Bryson went before the committee to name former Democratic Unionist leader Peter Robinson in connection with the case.

The then first minister has strongly denied seeking to benefit from the agreement involving US investors and the National Asset Management Agency (Nama).

Mr O Muilleoir was a Sinn Fein member of the committee at the time and political rivals have called for him to stand aside while a Stormont watchdog examines the episode.

The now Finance Minister issued a statement on Monday making clear he had "absolutely no knowledge" of the Twitter communications.

"The attempts to link me to the contacts between Daithi McKay, Thomas O'Hara and Jamie Bryson are no more than petty party politicking," he said.

"They have absolutely no basis in truth or fact. I had no part in or knowledge of these inappropriate communications.

"I will co-operate readily and fully with any investigation. I am absolutely confident the outcome of any such investigation will confirm that I was totally unaware of these contacts until they were publicised this week.

"My political opponents will also have their chance to contribute to the investigation but if they do they will be required to present evidence rather than speculation or innuendo. I am confident in predicting that they will fail to do so."

Mr McKay's fall from grace was precipitated by claims in Belfast newspaper the Irish News about his contact with Mr Bryson.

The Sinn Fein leadership has denied knowing anything of the back channel contacts.

The deal two years ago between Nama and US investment giant Cerberus, involving the £1.2 billion sale of a Northern Ireland property loan portfolio, has been dogged by controversy after £7 million linked to it was found in an Isle of Man bank account.

Critics have claimed the arrangement included multimillion-pound fixer fees.

Nama was established in Ireland at the height of the financial crisis to take property-linked loans off the books of bailed-out banks.

It sold 800 property loans to Cerberus, a multibillion-pound fund.

All parties involved in the 2014 transaction have denied wrongdoing.