Sean Kenzie has already incurred $NZ18,000 in medical bills but an insurance company is refusing to pay, according to sunlive.co.nz, and he is now in need of more treatment.
The report does not name the hospital in which Mr Kenzie is recovering from a smash on Phuket on Saturday night.
His brother Kane told the online site that Sean asked for full coverage and was surprised to find the insurance did not cover motorcycles.
Sean split his liver, punctured both lungs, broke ribs and still needs a major operation on his neck to reattach the muscles to his jaw, his brother says.
''They [the insurance company] never said to him motorbikes aren't included,'' Kane told the NZ site. ''He was going to a country where the primary transport is motorbikes.''
Mr Kenzie, who had been working as a roofer in Perth, was in Phuket waiting for his girlfriend, 26-year-old Amy Myles, to arrive so they could begin their holiday together.
Ms Myles had arrived in Phuket a day after Mr Kenzie only to find out that he was in hospital. It was the first overseas trip for both.
A Facebook page entitled 'Save Our Mates Life' has been set up to help raise money.