Police from the WA Major Fraud Squad are currently executing a warrant in the newsroom Western Australian newspaper The Sunday Times.

Sixteen officers are conducting an extensive search of the newspaper's office after interviewing the editor, Sam Weir, for about an hour.

The officers are searching for documents relating to a story written in January this year by staff reporter Paul Lampathakis, Perth Now reported.

The story was a political piece on the Carpenter Government which reported that Treasurer Eric Ripper had asked the parliamentary expenditure review committee to increase the State Government's advertising budget by $16m.

The money was earmarked for "strategic advertising campaigns", and the State Opposition alleged the money would be used to "buy" an election win.

Police searching Lampathakis' desk were requested to take particular note of anything from the "expenditure review committee", which is chaired by Mr Ripper.

The warrant is for: "Any and all documents pertaining to the information held by Sunday Times employees pertaining to the investigation conducted for the article titled Bid to buy Labor win: Ripper wants $16m for poll, published on page 3 of The Sunday Times, 10th February 2008, including source details, notebook entries, records of conversation, editorial notes, scribings, telephone records, any form of recording (electronic or otherwise) and records of conversation."

Staff have been told by Detective Sergeant Alan Jane that police have been posted on all the building's exits.

Anyone who leaves will have their names and details taken and will be searched in a "cursory" way for the items on the warrant.

The Sunday Times is owned by News Corp, the parent company of the publisher of NEWS.com.au