Four partners at the Belfast offices of KPMG have been arrested after HM Revenue and Customs (HMRC) started an investigation.
Representatives from the tax authority visited the offices of the big four firm yesterday.
It is understood the partners involved are Jon D'Arcy, Eamonn Donaghy, Arthur O'Brien and Paul Hollway. Donaghy is the head of KPMG's tax practice in Belfast.
The professional services firm has said that it does not have any indication that the investigation relates to the business of either KPMG or its clients.
A KPMG spokesperson said the firm was cooperating with the investigation and that the partners had been put on administrative leave.
An HMRC spokesperson said: “HMRC officers arrested four individuals from Northern Ireland yesterday in connection with suspected tax evasion. We can't comment further.”