New Zealand First leader Winston Peters is demanding to know why the Prime Minister has not told Defence Minister Mark Burton to order the Army to stop blocking public release of a report on a fatal bridge accident.

Keith and Margaret Berryman lost their farm through legal and other costs after the Labour Department's Occupational Safety and Health arm prosecuted them for the death of Inglewood beekeeper Kenneth Richards in 1994.

He was driving across the bridge leading to the farm - built by the Army in 1986 - when it collapsed.

In 1997 a coroner accused the Berrymans of not adequately maintaining it. The Army built the bridge as an exercise for engineers but did not tell the coroner of an internal report which the couple's lawyer, Rob Moodie, says details serious design and construction errors.

The Berrymans last month formally abandoned their fight for a new coroner's hearing after the Solicitor-General won a High Court decision stopping that report, by former Army engineer George Butcher, being used as new evidence.

But Dr Moodie has defied court orders and put the report on the internet. He said he had not breached a suppression order, but the rules governing High Court civil hearings requiring that if documents are discovered they must only be used for the proceedings.

In Parliament yesterday, Mr Peters asked when Helen Clark would show "leadership" and direct Mr Burton to make the report public.

Answering on her behalf, Deputy Prime Minister Michael Cullen said the Prime Minister had no intention of ordering the Defence Minister to act in breach of a court order.

Dr Cullen said the Berrymans were offered $150,000 from the Crown in 2001. That offer was still on the table.

But Mr Peters twice more asked why the Prime Minister would not direct Mr Burton to get the Army to behave "in a responsible way" and not in "this most despotic way" and allow the report's release.

Mr Peters also cited a 1998 newspaper report which quoted Helen Clark supporting the Berrymans' case after she visited the couple's Owhango farm during the Taranaki-King Country byelection.

"It's an issue of National having lost touch with its traditional constituency," she said.

"These people were persecuted by the Labour Department. They have constantly sought some relief from the Government and they've never had it."

On Wednesday Mr Peters tried to table the Butcher report in Parliament - for MPs' eyes only.

He was denied leave and blocked again yesterday.

Later he issued a statement saying the Government's involvement in the cover-up of the report was a disgrace.

United Future MP Murray Smith said: "This case is now bordering on being a serious miscarriage of justice through the abuses of process that are alleged to have occurred."