A 45-year-old man in south London was arrested on suspicion of fraud and an "amount of material was seized" in a search of his residential property, police said. The man, whose name was not released, was released on bail Wednesday afternoon.
The Scotland Yard probe has been running since August when allegations of wrongdoing in the bidding process were made by West Ham and the Olympic Park Legacy Company, whose board members decide the future of venues on the site of the 2012 Games.
During a London Assembly committee hearing last year, OPLC chair Margaret Ford accused Tottenham of ordering surveillance on all 14 members of the legacy company board.
Tottenham denies any allegations of spying or the illegal obtaining of information.
It emerged during a separate High Court case that a company, which a judge said was hired by Tottenham, had copies of a West Ham executive's telephone records that had been "unlawfully obtained by subterfuge."
The investigators allegedly employed by Tottenham were from the accountancy firm PKF, whose former partner Howard Hill was arrested last week on suspicion of fraud.
Police investigating the illegal procurement of information made their first two arrests last November. There have been no charges filed in the case.
PKF denies any unlawful activity and said it has had no communication with Hill since he resigned from the firm in December.
Tottenham previously insisted that it "did not instruct PKF to engage in any unlawful activity and PKF have confirmed that they did not."
West Ham's deal to take over the 486 million-pound (US$744 million) Olympic Stadium collapsed in October amid legal uncertainty.
The venue will now remain in public ownership and be rented out after the Olympics. West Ham has yet to decide whether to bid again or redevelop its existing Upton Park ground.