Olympic champion Daniel Wiffen has withdrawn from the World Aquatics Championships in Singapore due to the ongoing effects of appendicitis he suffered from in June.

The Magheralin man finished eighth in the 800m freestyle final on Wednesday despite making a good start in the defence of his title, but faded as the race progressed.

After that race, Wiffen said his “stomach was in pieces” after the halfway point.

Wiffen scraped into the final as the last qualifier from the heats, admitting he felt “really weak” after his heat, while on Sunday, the 24-year-old came in 16th overall in the 400m heats.

The 800m Olympic champion was due to begin the defence of his 1500m World title on Saturday, but upon reflection, has decided to withdraw.

“Just to let everyone know I have medically withdrawn from the World Championships in Singapore due to the appendicitis that I suffered from in June,” he said.

“Thank you for all the support in last night’s (800m) final. I wasn’t physically at my best, but I will be working towards getting back to full fitness and winning shape soon.”