Irish Timeseditor Geraldine Kennedy and public affairs correspondent Colm Keena are to appeal against a recent High Court order requiring them to answer questions from the Mahon tribunal.
They announced their decision to appeal to the Supreme Court today.
Last month the High Court ordered the two journalists to appear before the Mahon tribunal to disclose the source of an article about financial payments to Taoiseach Bertie Ahern.
It also warned the journalists that they may be found in contempt of court if they fail to do so.
The Planning tribunal sought the order under Section 4 of the Tribunal of Inquiry (Evidence) (Amendment) Act 1997, which permits the tribunal to seek the assistance of the High Court where a person has failed to comply with its orders.
The proceedings arise from publication in The Irish Timeson September 21st, 2006, of an article written by Mr Keena and entitled: "Tribunal examines payments to Taoiseach".
The article was based on information contained in a letter from the tribunal to businessman David McKenna sent on June 29th, 2006. Mr McKenna is one of a group of 12 businessmen who made payments totalling £38,500 to Mr Ahern in 1993 and 1994. The letter was sent to Mr Keena.
The tribunal is trying to find the source of the information.