Kenya's hopes at the London World Athletics Championships were dealt a blow on Tuesday after world 400 metres hurdles champion Nicholas Bett pulled out with a recurrent right leg injury.

Bett will join the list of athletes who will not defend their titles from Beijing 2015 including Jamaican Usain Bolt in the 200 metres, Ashton Eaton in decathlon and Matej Toth in the 50 km walk, reports Xinhua news agency.

And the absentees in women's events include Shelly-Ann Fraser-Pryce in the 100m, Vivian Cheruiyot in the 10,000m, Christina Schwanitz in shot put, Jessica Ennis-Hill in heptahtlon and Liu Hong in 20km walk. The World Championships will be held between August 4 and 13 in London.

Bett's manager Jukka Harkonen confirmed that his athlete will give the championships a bye, saying a serious stress fracture on his fibula bone is to blame.

Bett is experiencing sharp pain in his right leg and this was amplified during the Diamond League in Doha on May 5.

"The pain came again after the Shanghai meeting on May 13 and he started treatment in Nairobi," said Harkonen. "We advised him to take leave, but he will not recover in time for the championships."

An MRI scan in Nairobi cleared Bett of any injury, but failed to explain the pains, which forced his manager to fly him to Lahti, Finland for further check-up and treatment.

"We examined Bett on June 8 and it was discovered that Bett had a serious stress fracture," explained Harkonen.

Bett would start two weeks of full rest and then another four weeks of pool work before starting easy jogging after six weeks.

He missed the National Championships and Trials on June 23-23 in Nairobi. Bett is expected to resume training next month and hopes to make it to the 2018 Commonwealth Games.

"It's disappointing since my main target was to defend my title," said Bett in Nairobi. "I will be back in good health and stronger for the Commonwealth Games."

Head coach Julius Kirwa said Bett's injury is a blow to Kenya's chances at the London World Championships but believes his void will be filled by his brother Haron Koech, who is part of the Kenya team.