SYDNEY (AFP) - New 50-metre freestyle world record holder Eamon Sullivan said he has laughed off drug insinuations and lifted his confidence ahead of this year's Beijing Olympics.

The Australian sprinter pulled out the unexpected world record here last month, raising the suspicions of reigning Olympic champion Gary Hall Jnr.

The American compared Sullivan's huge drop in time in breaking the 50m freestyle world record to those of drug cheats.

Sullivan said Hall's comments were laughable and only motivated him to confirm his times at this weekend's Australian Olympic trials.

"I actually did laugh when I heard," Sullivan told a press conference Friday.

He said Hall's comments had lifted his confidence and he felt primed to chase his own benchmarks during the eight-day trials, which start in Sydney on Saturday.

"It is something that makes you realise that you are doing your job, if you have people talking and they are worried about the work you are doing inside the pool," he said.

"So I guess it is a bit more of a confidence-booster if anything."

Sullivan said he had no doubts the world record could again be under threat after breaking Russian Alex Popov's 50m world mark of 21.64 seconds by 0.08 secs with a new time of 21.56secs last month.

"Everything has been going well in training there has not been any distraction," he said.

"I am very confident I can get close if not faster (than my best times)."

Meanwhile Grant Hackett's coach Ian Pope said the two-time Olympic 1500m champion was ready to destroy the field at the trials.

"In the warm-up today he was like a tiger coming out to kill somebody," Pope said.

"He is just ready to get out there and rip them apart."

The Australian swim team captain and world record holder said he was refreshed and confident as he pursues a third straight Olympic title in the 1500m.

Hackett is trying to rebuild his career since bombing out at the 2007 world championships in Melbourne in both his 400m and 1500m world title events.

Only the top two swimmers in each event at the Australian trials can qualify for individual swims in Beijing.

"You will see more tears on this pool deck than you will in any moment in the past four years," Hackett said.

"Certainly, dreams get broken and dreams get made."

Australian swimmers currently hold eight long-course world records heading into the Olympic trials.

Australian and Commonwealth 100m freestyle record holder Libby Lenton announced Friday she will be swimming at the trials under her new married name of Libby Trickett.

She married fellow swimmer Luke Trickett in April last year.