The bank said in a statement that over 12 weeks, each participant would use either a key fob, fitness-style wristband or a watch-strap clip to make their daily purchases.
Bankwest managing director Rowan Munchenberg said the company was looking to see where "this toe in the water trial could take us. We need to continually evolve and adapt to meet the quickly changing needs of our customers".
"Our customers’ lives are so varied and so we need to look at offering a range of payment methods that fit their lifestyles. Students, self-employed, FIFOs, retirees, regional or metro – there really can’t be a one size fits all approach anymore.
The bank began to experiment with the idea after one of its regular hack days at which new ideas are discussed.
Bankwest configuration engineer Minh Dang, who was part of the Hack Day team that devised the wearables trial, said: "When the idea of these wearables came up at the Hack Day people got really excited.
"It’s so great to see it now becoming a reality in the trial. There’s not many places where you can see something start at such a small level and then become a reality."
Participation in the trial has been voluntary and detailed feedback is provided on the experience. Data is also being gathered on how people use the new tech along with contactless features on existing debit and credit cards and phones.
“We think we’ll see people starting to adapt to whatever comes to hand most easily,” said Munchenberg.
“If they’re buying petrol and have their keys in their hand they may well pay with their key fob. If they’re out for a run and stop for a drink they could swipe their wristband. The technology is just as secure as in people’s cards – it’s just in a different form."