Bernard Kevin McGrath, 66, is challenging the minister's decision through a judicial review hearing at the High Court in Christchurch.
After several hearings at district court and high court jurisdictions, it was left up to Ms Collins earlier this year to make a final decision on whether McGrath be deported to Australia to face 252 child-sex abuse charges.
In August, after "careful consideration", Ms Collins issued an order for his surrender across the Tasman.
But today, McGrath's lawyer, Phillip Allan said that the minister came to some wrong conclusions in her judgement. There was evidence before her that said McGrath had no support network in Australia, Mr Allan said in a submission that raised questions of natural justice.
The minister was also told of concerns that McGrath might not be able to obtain the "significant support he would need from lawyers to properly defend the matter should he be extradited", he said.
But while Ms Collins said he could apply for legal aid there, there would be no guarantee it would be granted. "She could have sought to obtain further information about the legal aid system or she could have sought assurance from the Australian authorities that Mr McGrath would be eligible for legal aid and that he would receive legal aid with the same basic rights one would expect in New Zealand. But she didn't do that," Mr Allan told the court today.
He added there were differences between the two legal aid systems, including a cap system on fees in Australia.
The hearing, before Justice Cameron Mander, continues.
By Kurt Bayer of NZME. News Service
