An important step on the road to Rio will be taken by New Zealand swimmers at the national open champs in Auckland starting on Tuesday.
Swimmers who want to be competitive on the world stage in Rio next year, will need to stake their claim in the four-day meet at the West Wave Aquatic Centre in Henderson.
The championships are the sole trial for both swimmers and Para-Swimmers to qualify for their respective world championships this year.
Para-swimmers will contest their world championship in Glasgow on July 13-19 while the FINA world championships will be staged in Kazan, Russia in early August.
Swimming New Zealand High Performance Director, Luis Villanueva said performances this week in Auckland will be an important litmus test.
"If swimmers want to make semifinals and finals in Rio next year, then they will need to perform at the world championships this year. To achieve that then they not only need to qualify here but stand up and show they want to be a force next year," Villanueva said.
"The qualifying standards are demanding and in line with the overarching criteria set by the NZOC for qualification for Rio 2016.
"The first step is to qualify this week but even more important is that these swimmers need to then work harder because they must swim faster in Russia and faster again next year."
The men's standards overall are a tick slower than for the Commonwealth Games while the women's standard's have tightened a fraction.
Five swimmers achieved individual qualifying times in 14 events for the last world championships two years ago, with three of them expected to lead the way this week - Lauren Boyle, Matthew Stanley and Glenn Snyders.
Fourteen swimmers qualified as individuals and in relays for Glasgow last year, with 10 in action this week.
Boyle, will lead the way following world class swims at the Australian Championships last week which pleased the 27-year-old who has been training under Denis Cotterell in Queensland.
"My preparation for the trials has been good and I'm focussed on swimming as fast as I can," said Boyle. "It is vital to race well this week and learn from new competition experiences leading in to the Olympic year."
Stanley, 23, the national record holder in 200m and 400m freestyle, is also with Cotterell and returning to his best after some time out of the pool last year.
"That form is slowly returning although I am not swimming as fast as I want to. I am enjoying the environment in Queensland and have trained well," Stanley said.
"The target is to qualify and then I know I have some very hard work ahead of me to produce my best in Kazan."
Snyders, chasing a third Olympics in Rio, has returned from his base in Los Angeles where he trains under famed American coach Dave Salo in a star-studded programme.
The breaststroker, who turned 28 last week, attended his first world championships a decade ago. After a medal in the Pan Pacific Championships last year, Snyders is looking to again qualify in all three distances this week.
"I see the worlds as a stepping stone towards Rio," Snyders said.
"Obviously I want to do well at the world champs so all my focus for this year will be on that and making the final in the 50m and 100m breaststroke, which will set me up nicely for Rio next year.
"I am confident in myself and preparation. Since taper has started I am feeling good in the water. I just need to be patient - that is the hardest part of tapering."
There are also some new exciting stars on the horizon led by the trio who all won medals in global youth competitions last year comprising 15-year-olds Gabrielle Fa'amausili (Auckland) and Bobbi Gichard (Hawkes Bay) along with talented Waikato swimmer Bradlee Ashby.
They will be pushing to qualify under the lower threshold provision for swimmers born since 1995 who are targeted for the 2020 Olympics.
Swimmers will be pressing their claims in both individual and relays for the world championships that will also offer the first qualifying opportunities for relays and marathon swimming for Rio. Rotorua's Kane Radford and New Plymouth's Charlotte Webby have already qualified for the world championships in the 10km marathon swimming events.
There are a number young swimmers returning from USA where they are on college scholarships to add real interest to those based in Australia and at home in New Zealand this next week.
The Para-swimmers sparked some brilliance in the national championships last here where Pascoe and Fisher set nine world records between them.
The super-star pairing will likely lead the way along with Commonwealth Games swimmer Nikita Howarth and the return of double Paralympics and world champion Cameron Leslie.
The heats run from 10am daily, with finals from 7pm.