Triple Olympic gold medallist Stephanie Rice booked her flight to July's world swimming titles in Rome while fellow winner Nick D'Arcy knows his boarding card is far from secured.

Rice put aside fitness and niggling injuries to eclipse young contender Emily Seebohm in the 200m medley after earlier finishing second in the 200m freestyle at the trials in Sydney.

After she had wrapped up two individual swims on the opening night, D'Arcy (1minute 54.46 seconds) took out the 200m butterfly.

He smashed his national record by two thirds of a second in earning his spot back on the Australian team after being famously booted off the Beijing Olympic squad.

The 21-year-old Queenslander now has an anxious week and a half before his sentencing hearing for assaulting Simon Cowley on Friday week.

That will decide whether he will be in the Eternal City or the big house this July.

D'Arcy said he would be pumped if he gets the chance to swim in Italy and that he had grown up in the last 12 months.

On his tarnished image he said: "I don't think it could have got much worse, the only way to go is up".

Seebohm earlier put up a stiff challenge before Rice powered away in the final lap. Rice said she was pleased with the effort after a quick turnaround following the 200m freestyle.

"I barely had my cap and goggles on before I walked out for that race," she said.

"I was not as focused as I would have liked but to come out with an 11.00 (2:11.00) was a really solid swim. "With the preparation I have had I am really happy with the swim tonight."

Seebohm (2:12.75), who is better known as a backstroker, warned Rice that she was on her way in the medley.

"I am only 16 now, I really think that I have a lot of room to improve," she said. "I am still growing and I still have to develop all my muscles because I am only doing a certain load because of my age.

"When I get to that 20 age I reckon I will be hitting pretty good times too."

In the women's 200m freestyle, Meagen Nay (1:57.90) managed to fight off Rice (1:57.98) in a tight finish with 16-year-old Ellen Fullerton (1:58.05) coming in third to book her first place on a senior national team.

Bronte Barratt (1:58.19), a member of Australia's Olympic gold medal winning 4x200m relay in Beijing last year, finished fourth in a sign the relay for Rome is in good health.

The men's 400m freestyle entered the post Thorpe-Hackett era and it was Robert Hurley (3:46.64) that seized the title. He brushed aside teenager Ryan Napoleon (3:48.02) in the final two laps as they both earned trips to Europe.

Hurley and Napoleon have also put their names up for the 1500m later in the week as Australia search for a new distance star following Hackett's retirement last year.

Tom Wald
AAP