Nine publishing is set to expand its Editorial Code of Conduct to clarify rules around signing petitions, as the publisher prepares to lift restrictions placed on editorial staff who signed an open letter regarding the coverage of Israel-Gaza in November.

Those restrictions, which saw signatories prevented from reporting on or producing coverage about the Middle East conflict, are due to be lifted on May 24 as per an all-staff slack message sent to Nine's publishing staff earlier today.

Editorial management issued that Nine's Editorial Code of Conduct's "existing section on impartiality will be expanded to make clear that the signing of open letters or petitions may constitute a breach of the code, and that signatories may be directed to undertake different work duties to avoid any perceived or actual conflict of interest."

The message was signed off by Nine newspapers' executive editor, Luke McIlveen, Sydney Morning Herald editor, Bevan Shields, The Age editor Patrick Elligett, and national editor of The Sydney Morning Herald and The Age, David King.

"Our mastheads are committed to independent journalism and impartiality. The signing of an industry open letter by some staff led to them being unable to participate in reporting or producing coverage about the war in Israel and Gaza. This will end on May 24 - six months after the decision was implemented.

Nine was met by criticism from the Media, Entertainment and Arts Alliance (MEAA) in November of the publisher's crackdown on editorial staff who signed an open-letter petitioning newsrooms to cover the events in Israel and Palestine with “integrity, transparency and rigour”.

A slack message sent by then-executive editor at The Age and The Sydney Morning Herald, Tory McGuire, warned editorial staff that signatories to the letter “would be unable to participate in any reporting or production relating to the war”.

ABC news director, Justin Steven, also issued a similar warning to staff at the public broadcaster, writing in an all staff message that "maintaining trust and credibility as an ABC staff member means you forgo the opportunity to share your opinions about stories which you report or may be involved in.”