Key Points:

Prime Minister Helen Clark says there will always be suspicions about the strategists used by the National Party because it isn't honest about them.

"I think the good thing is that light is now being shone on the tactics of these particular Tory tricksters," she said at her post-Cabinet press conference yesterday.

"The National Party can use who it likes, but one of the problems is they're not open about it - you will not get a straight answer from them about who they use."

Investigative author Nick Hager reported in the Sunday Star-Times that National leader John Key had hired Australian political strategy company Crosby/Textor.

His report, which included dates and details, has raised the spectre that National still has problems with its security, two years after Hager based his book The Hollow Men on hundreds of internal party emails.

A spokesman for Mr Key yesterday said he would not confirm the party had hired Crosby/Textor because it did not comment on the identity of anyone they contracted. Crosby/Textor was used by former National leader Don Brash, and their dealings make up some of the emails in The Hollow Men.

The company has courted controversy and there have been claims of dirty tactics.

Lynton Crosby was largely credited for former Australian prime minister John Howard's 2001 Tampa campaign and the company was recently behind London mayoral winner Boris Johnson's campaign.

Helen Clark said Crosby/Textor had "quite a reputation".