Sydney radio station 2GB breached the commercial radio code when it claimed children visiting Parliament House in Canberra would no longer get snacks and water, a media watchdog has found.

The Australian Communications and Media Authority (ACMA) says the station's Ray Hadley Morning show breached the code when it broadcast a report based on a newspaper article making those claims on June 25 last year.

The claims were made after the then Treasurer, Wayne Swan, released an media statement saying the report was incorrect.

"The Australian Communications and Media Authority found that, in all the circumstances, 2GB had not used reasonable efforts to ensure that the factual material broadcast was reasonably supportable as accurate," ACMA said in a statement on Wednesday.

"Given Mr Swan's media statement ... the ACMA found that more was required (to ensure the material was accurate) in this particular circumstance".

ACMA acknowledged Mr Hadley corrected the inaccuracy in subsequent broadcasts.

However he failed to state that original report was incorrect, the authority said.

ACMA and 2GB were discussing "remedial measures", it said.

Comment was being sought from Harbour Radio.