Protesters are rallying outside the County Court in Melbourne to support two Age investigative journalists who are expected to be ordered to reveal confidential sources.

Award-winning reporters Nick McKenzie and Richard Baker have been subpoenaed to give evidence in a case against former banknote officials, who are accused of bribery.

The Age investigative reporters Nick McKenzie, left, and Richard Baker. Credit:Rebecca Hallas

Baker and McKenzie are expected to be asked on Monday to reveal the source of a December 8 report that an alleged bagman from Indonesia would testify against the seven accused as a star witness for the prosecution.

The Media, Entertainment and Arts Alliance has organised the rally to support the journalists, who, as union members, are obliged to respect their source's anonymity. Victoria recently introduced shield laws for journalists, to prevent them from being forced to reveal confidential sources, but the case began before the laws came into effect.