Two-time world champion Kento Momota said Thursday he is retiring from international badminton aged 29, ending a top-level career that never recovered from a car crash four years ago.

Momota, who had already missed out on a place at the Paris Olympics, will play for Japan for the last time at the Thomas Cup in China later this month.

The former world number one will only feature in domestic competitions in Japan after that and not on badminton's World Tour.

"I have made this decision because it feels like I have reached my physical and mental limit in trying to get back to being the best in the world," Momota, now ranked 52, said in a statement.

Momota was once badminton's undisputed king, winning 11 titles in 2019 and losing just six of the 73 matches he played that year.

But his life was turned upside down in January 2020 when the vehicle taking him to Kuala Lumpur airport crashed hours after he won the Malaysia Masters.

The driver was killed and Momota needed surgery to repair a fractured eye socket.

He suffered double vision and struggled to regain his previous form when he returned to competition after a year out of action.

He lost in the opening round at the Tokyo Olympics in 2021 and fell at the first hurdle in four of the first five tournaments he entered the following year.

He was also hampered by injuries and saw his world ranking plummet as former rival Viktor Axelsen established himself as badminton's top player.

Momota, who was embroiled in a gambling scandal earlier in his career, ended a two-year title drought when he won the Korea Masters in November last year.

Momota had targeted this summer's Paris Olympics but his national ranking was not good enough to earn him a spot in Japan's team.

He was banned from selection for the 2016 Rio Olympics for gambling at an illegal casino. (AFP)