A general view of Palace of Westminster and the Queen Elizabeth Tower which contains the bell known as 'Big Ben' in London. File picture: Alastair Grant/AP

London - Police are investigating a suspicious substance at the British parliament in Westminster, with two people taken to hospital as a precaution.

Police said they were investigating reports of a suspicious package at the Norman Shaw Buildings, where many lawmakers have their offices, on the parliamentary estate.

"We are aware of a potential situation involving a suspicious substance which the Met Police are investigating," a spokeswoman for parliament said in a statement.

"There has been no evacuation, but the affected area has been cordoned off."

Last month, police investigated white powder sent to an office in parliament, which was later found to be harmless.

Police said specialist officers were assessing the suspicious package on Monday.

"London Ambulance Service attended and two people, a man and a woman, have been taken to hospital as a precaution," they said.