The appointment of Bertha McDougall - whose policeman husband was murdered by republicans - as Victims' Commissioner is to be legally challenged.
Bertha McDougall's RUC Reservist husband killed by INLA
The post is intended to promote the interests of victims of the Troubles.
The widow of Sean Downes - killed by a plastic bullet in 1984 - wants the appointment reversed. Mrs McDougall's husband was murdered by the INLA 1981.
Brenda Downes wants a judicial review on the grounds that Mrs McDougall does not command cross-community support.
She also said the appointment was a sop to the Democratic Unionist Party.
Papers were lodged in the High Court by Mrs Downes' solicitors, but before the case can be heard a judge has to grant leave.
Solicitor Paul Pierce said: "This is an extremely important and sensitive issue for the families of victims and to that end it is a significant challenge which needs to be heard as soon as possible."
The commissioner is to help victims of the Troubles
In 1986 an RUC reservist was cleared of the manslaughter of Mr Downes at an internment anniversary rally.
His widow, who has a daughter now aged 22, was awarded undisclosed damages in 1989 in a compensation action against the chief constable.
Mrs Downes is seeking an order quashing Mrs McDougall's appointment and an immediate halt to the work she is doing pending the outcome of the case.
She also wants the appointed to be declared illegal because she claimed the secretary of state did not give enough weight to the need for consultation and the need for "actual and perceived independence".
Mrs McDougall, 59, a former school teacher, helped set up the victims' group, Forgotten Families.
Her appointment as Victims' Commissioner was announced by Northern Ireland Secretary Peter Hain in October 2005.