Chief Ombudsman John Belgrave has ruled that secret notes partly released by the Government last year to embarrass National Party leader Don Brash should remain confidential.

Mr Belgrave said releasing the full transcript of the "gone by lunchtime" notes under the Official Information Act, as requested by the Herald, could prejudice New Zealand's international relationships and the public interest.

Prime Minister Helen Clark, and other Cabinet ministers at the time, sparked a bitter row with National last May after making public a small part of what would normally be the diplomatically protected notes of a meeting between Dr Brash and six visiting United States senators.

The released portion, written by a Ministry of Foreign Affairs and Trade official, claimed Dr Brash told officials that if it was up to him, the ban on nuclear ship visits would be "gone, by lunchtime even".

The Government broke the convention protecting the privacy of talks between New Zealand and foreign politicians in making public the comment for political purposes, just as National was about to release a review of its nuclear policy.

Dr Brash has said he could not recall making the remark, and the leader of the American delegation, Senator Don Nickles, said they received no assurance National would drop a ban on nuclear-propelled ship visits.

After the Herald reported Senator Nickles' comment, Foreign Affairs Minister Phil Goff released a copy of the note containing the "lunchtime" remark. But he refused to release the full report of the meeting, or the notes of what he told the Americans when he met them.

Mr Belgrave, who delivered a provisional decision saying the full transcript would remain private last July, has now confirmed that position.

He has ruled the notes of the Brash meeting were "subject to an obligation of confidence" under the law.

To disclose them would be likely to prejudice the public interest and New Zealand's international interests.

"I consider it is in the public interest that Members of Parliament should feel able to conduct free and frank discussions with overseas political figures."

He said Mr Goff and Dr Brash had confirmed it was their expectation for each of their meetings to be confidential, as is the usual convention.