"We're in a power sport which is normally related to masculine tendencies ... where you've got that aggression, you've got the right hormones, then you can lift bigger weights," he told AAP.
"If you've been a male and you've lifted certain weights and then you suddenly transition to a female, then psychologically you know you've lifted those weights before.
"I personally don't think it's a level playing field. That's my personal view and I think it's shared by a lot of people in the sporting world."
Hubbard was unavailable for interview but Olympic Weightlifting New Zealand said she met International Olympic Committee regulations related to acceptable testosterone levels.
Tasmanian Kaitlyn Fassina is the only Australian woman likely to compete in Hubbard's 90kg-plus category on the Gold Coast.
Keelan said the AWF had written to the IOC and the International Weightlifting Federation raising concerns about transgender athletes but were yet to hear back.
The vexed issue of transgender inclusion in elite sports was debated in Australia recently when former male handball player Hannah Mouncey was barred from the AFL Women's competition.
The 190cm, 100kg ruck transitioned in 2015 and was understood to have met IOC regulations but was told she must wait until next year to nominate for the draft.