Three Sinn Féin MLAs, including the former regional development minister Conor Murphy, are being sued by a former director of Northern Ireland Water.
The cases have been taken by Declan Gormley.
He was one of four executives sacked by Mr Murphy two years ago over the way the government-owned company was being run.
The other two assembly members he is to sue are Willie Clarke and Cahal Boylan.
It is understood the claim against Mr Clarke and Mr Boylan relates to comments written in an article and press release.
A separate writ against the Department for Regional Development, in which Mr Murphy, is named involves a claim of libel and other issues in public office.
Mr Gormley and others at NI Water were sacked over the way contracts were awarded at the company.
He has always denied any wrong-doing.
Mr Gormley’s solicitors, John McKee and Company, have confirmed they are acting on his behalf in proceedings against Mr Murphy, the Department of Regional Development and the two other Sinn Féin MLAs.
Madden and Finucane solicitors have confirmed that they are representing the Sinn Féin MLAs and said that they would be robustly defending their clients.
