The Treasury is “seriously disappointed” in US business newspaper The Wall Street Journal following a breach of lock-up protocol on reporting on Budget 2022.

The Wall Street Journal had agreed to comply with lock-up protocols as a condition for attending the restricted briefing.

The WSJ "proactively informed a Treasury official" just after 1pm that they had breached the strict 2pm embargo, the Treasury’s deputy secretary for budget and public services, Struan Little, said in a media release.

“We are extremely disappointed with this serious breach of lock-up protocol. The embargoed information made available to the 200-odd people who attended the event was both restricted and sensitive," he said.

The Treasury is now working with the Wall Street Journal to “clarify and understand the action” leading up to the breach of the embargo.

“Once we are confident that we have established the facts, we will advise the Wall Street Journal of the consequences of their actions."

An internal investigation, overseen by the Budget Governance Group, has since been launched.

It will include a review into the existing protocols to ensure they remain fit-for-purpose for future lock-up events.