Premier Barry O'Farrell has dismissed calls for him to suspend three of his MPs over an alleged corruption scandal, saying until the corruption watchdog made a statement on its activities the matter was "pure speculation".

The Independent Commission Against Corruption raided the offices of central coast Liberal MPs Chris Spence and Darren Webber on Friday, seizing computers and documents.

Darren Webber.

The raids are believed to be linked to allegations, revealed by Fairfax Media last year, that two staff members of NSW energy minister Chris Hartcher, another central coast MP, funnelled political donations through a front company before the 2011 state election.

Opposition Leader John Robertson has called for Mr O'Farrell to suspend Mr Spence, the member for The Entrance, and Mr Webber, the member for Wyong, while Greens MP John Kaye said Mr Hartcher should be stood down until ICAC resolved the matter.