Daniel Wiffen and Mona McSharry lead Irish challenge at World Aquatics Championships in Doha

Daniel Wiffen and Mona McSharry are once again Ireland's main medal hopes at the World Aquatics Championships in Qatar, which get under way on Sunday.

The week-long meet is also an Olympic qualifier, with Ireland looking to add to the three swimmers who have already booked their tickets to Paris Games this summer.

Wiffen, McSharry and Ellen Walshe - who is not in Doha this week - have already pre-qualified and this meet and the Irish Olympic trials at the National Aquatic Centre in April represent the final opportunities for Olympic qualification.

Wiffen goes to Doha ranked second fastest in the 800m freestyle, an event in which he is the short course world record holder, and third fastest in the 1500m.

He will be the first Irish swimmer in action early on Sunday morning in the heats of the 400m freestyle, where he will come up against reigning Olympic champion Ahmed Hafnaoui of Tunisia.

Wiffen may use his opening event as a preparation for the 800m and 1500m later in the week, which will also feature Hafnaoui, who won double gold at last year's World Championships in Japan.

Ireland has never won a long course World Championships medal.

Wiffen finished fourth in both the 800m and 1500m freestyle in last year’s meet in Japan.

"I'm doing the three events but depending how it shapes up this week in Doha that might change for the Olympics," Wiffen told the BBC.

"And if I make a mistake at this World Championships, I've got six months until the Olympics to fix it.

"It's also the chance to tick another box. I mean, no Irish swimmer has ever won a medal at the World Championship long course and, dare I say it, no Irish swimmer has ever become a world champion and hopefully we can do that and be the first to do that too."

Wiffen will be