West Ham United are taking legal action against Tottenham Hotspur and The Sunday Times over allegations surrounding the validity of the Olympic Stadium bidding process.
The club said it was treating claims made by the newspaper "with the utmost seriousness" and insisted it was "certain of the robustness" of its successful bid to take over the east London stadium following the 2012 games.
It comes days after the Olympic Park Legacy Company (OPLC) confirmed an employee had been suspended after it was discovered she was working as a consultant for West Ham during the bidding process.
The woman, who is not being named, has been suspended with immediate effect while the potential clash of interests is investigated.
A West Ham spokesman said: "West Ham United can confirm the club are taking legal action in relation to allegations made in today's Sunday Times.
"We are certain of the robustness of our successful bid for the Olympic Stadium."
The OPLC board, in charge of securing the future of the Olympic Park site, voted 14-0 in February to make the Hammers the first choice to move into the £486 million stadium.
They were in a head-to-head contest with Tottenham.
On Friday the OPLC revealed it had suspended one of it's employees following revelations about her work status.
The OPLC released a statement saying: "It has come to our attention that an employee of the Olympic Park Legacy Company has been undertaking paid consultancy work for West Ham United FC. The company had no knowledge of this work and no permission was given to undertake it. This individual had no involvement whatsoever in our stadium process."
West Ham said it undertook an initial internal investigation which established that the work carried out by the individual was "not connected in any way to the bidding process for the Olympic Stadium but procurement project management thereafter".
The club added: "We are of the firm view that the integrity of the bidding process has not been compromised. We consider that the bidding process was robust and believe that remains the case."