National leader Don Brash today apologised for letting down his colleagues by not telling them earlier he suspected the Exclusive Brethren was behind a pamphlet campaign attacking Labour and the Greens.

Both Labour and Green politicians have accused Dr Brash of lying after he denied knowing about Exclusive Brethren pamphlets attacking Labour and Greens and then admitting yesterday he had been told about their distribution.

Earlier this week National deputy leader Gerry Brownlee denied anyone in National knew about the pamphlets, but later Dr Brash admitted he had prior knowledge of the campaign.

Today, Dr Brash admitted he had let down his campaign strategy team by not discussing the issue with them.

He has now apologised to colleagues and Mr Brownlee.

"I put him in a very awkward spot. He was not aware of this (Dr Brash's knowledge of the campaign) and he therefore denied the National Party was aware of it."

He said he had not discussed the Exclusive Brethren campaign because he believed it was not a "big deal".

He apologised to the public for any confusion caused over the issue and said he had not deliberately misled anyone.

Dr Brash also hit out at journalists today suggesting they may be politically biased.

Dr Brash said questions should be asked about journalists who belonged to the Engineering Printing and Manufacturing Union as his party complained over that union and others funding pro-Labour advertising.

Dr Brash says his political opponents and the media were linking together non-related events and questions about the Exclusive Brethren, his meetings with them, their opposition to the Government and the smear pamphlets.

Dr Brash's explanation is that when he was first asked about the pamphlets he did not know they were the ones being circulated by the Brethren, so he said he didn't know who was responsible for them.

When he discovered their origin, he confirmed the Brethren had told him they were going to distribute pamphlets condemning Labour and the Greens.

Questioned further about the pamphlets this morning Dr Brash said many other organisations sent out material both for and against National and Labour and he did not keep track of who was responsible.

"It is not my business to finger a particular group putting this thing out," Dr Brash said.

If there was any confusion about his knowledge of events, Dr Brash said he apologised for that because it had distracted from the election campaign.

"Talking about distraction, nobody seems concerned of the fact that most of the reporters at Radio New Zealand are members of the engineers union, which is actively campaigning against the National Party," Dr Brash said.

Engineers' union secretary Andrew Little said Dr Brash's suggestion of political bias was unwarranted.

Journalists, who were union members, had no links with the union's political activities.

Dr Brash's attack was a sign he was under pressure.

"It is a classic case of trying to shoot the messenger, and it does Dr Brash no credit," Mr Little said.

National deputy leader Gerry Brownlee continued the attacks and in particular attacked National Radio as "Radio Labour".