The State Services Commission has widened its investigation into who leaked information about restructuring at the Ministry of Foreign Affairs and Trade, but the Labour Party says it should be dropped.
At the same time, unions representing staff at the ministry are taking legal advice after being called to appear before the inquiry.
The State Services Commission set up the investigation after the Government became outraged at information being leaked to Labour's foreign affairs spokesperson Phil Goff.
Mr Goff says he has not been approached to appear before the investigation and Foreign Affairs Minister Murray McCully should abandon his witch-hunt.
The Public Service Association says that as the union is an independent organisation that is being asked to appear before the inquiry, it wants to establish what its legal position is.
nNtional secretary Brenda Pilott says the inquiry is an unusually high-level one and union members will need to have good advice about it also.