Gym bragging rights will be on the line this Saturday when Excel Fitness Wollongong hosts its first open Olympic weightlifting competition.

The sport of Olympic-style weightlifting has long been seen as a niche activity but the explosion of the CrossFit phenomenon has brought the activity into the fitness mainstream.

Organiser Jason Chin admits he wasn't expecting the number of lifters from several Wollongong gyms the competition has attracted.

"I was actually very surprised," Chin said.

"It came about because I train a few guys in Olympic weightlifting and I wanted a way to test them," he said.

"I was just going to do a small competition amongst my guys but, as it turned out, someone saw it on Facebook who also does weightlifting and they were keen to jump in as well.

"That got me thinking I could go round and ask a few clubs to see if anyone else was interested and everyone I asked was very keen.

"As it turned out, we've got seven different clubs that'll be competing. There's a few CrossFit clubs."

The only categories are male and female, and the competition will be judged on the percentage of body weight lifted, he said.

"We've got the clean and jerk and snatch, and competitors get a combined total and that's what they're judged on."

The CrossFit craze has attracted criticism from lifting purists for teaching poor lifting techniques, but Chin expects the local CrossFit athletes to acquit themselves well.

"They get a bad rap because they do at times have some bad form but they do have some really good lifters. I'm expecting them to go well."