His father, Arron Rees said as a parent it was heartbreaking to see the bike stolen.
"We locked the bike up to a lamppost, went in and ordered, walked up to the window to make sure the bike was alright where it was and it was already gone ... In a matter of two minutes."
Bayleigh now has a new bike after his girlfriend's parents were able to pay for a 2000 euro (NZ$3113) bike to be built for him.
Mr Rees said they travelled on a "pretty tight budget" and planned to fundraise to pay for the new bike when they arrived back in New Zealand.
Bayleigh was having a new bike made specifically for him, trying to match it to his old model as much as possible.
They were building a bike using basically the same frame as the one which was stolen, Mr Rees said.
"It's not easy to jump on a new bike, even at this level. A familiar bike is a good thing.
That's why we've strived to get one similar to what he had.
"Bayleigh works so hard at what he does. For this to happen just absolutely pulled my guts out for him."
Earlier today Bayleigh's mother Raylene Rees said her son arrived on Air Malaysia flight MH16 - which was heading in the opposite direction to MH17 and was shot down over the Ukraine on the same day.
"It's been a quite horrendous 48 hours," Ms Rees said.
- Additional reporting by Rebecca Quilliam