A 25-year-old man on Tuesday denied murdering British MP David Amess, who was stabbed to death while meeting constituents earlier this year.

At a hearing at the Old Bailey court in central London, Ali Harbi Ali pleaded not guilty to murder and preparing acts of terrorism.

Ali, from north London, was arrested at the scene of the stabbing at a Methodist church in Leigh-on-Sea in southeast England, on October 15.

Amess, a 69-year-old father of five, was a long-serving member of parliament for Prime Minister Boris Johnson's Conservative party.

His killing was the second of a British MP in the past five years, and has led to calls for better safety for elected representatives.

Ali, wearing a blue sweatshirt and grey jogging bottoms, spoke only to confirm his identity and enter his pleas at the brief hearing.

The separate charge of preparing acts of terrorism is alleged to have taken place between May 1, 2019 and September this year.

He was remanded in custody. A trial date has been set for March 21 next year.