Hunter has acted in several civil and criminal cases following finance company collapses.
"Mr Xiao is unrepresented and has a very poor grasp of English," Justices Mark Cooper, Helen Winkelmann and Murray Gilbert said in their judgment today.
"He explained that he had sought representation but could not afford a lawyer, nor find one willing to represent him on legal aid.
"It is very difficult for any unrepresented litigant to make their way through the procedural thicket of waiver of security for costs, waiver of fees and the requirements of [the law]."
The Beijing-born man's proficiency with English has already been commented on by a judge when Xiao unsuccessfully attempted to set aside his bankruptcy notice.
Associate Judge Peter Andrew said a lawyer who speaks Mandarin would have been an advantage for Xiao at the hearing but "far from necessary".
"Mr Xiao represented himself before me. He presented submissions in English in a competent fashion and with minimal assistance from his interpreter," Judge Andrew said.
"Mr Xiao has lived in New Zealand since 1989 and I find that he has exaggerated the extent to which his lack of proficiency in English might have prejudiced him."
Xiao wishes to argue that the High Court reached its decision on the financial penalty and his disqualification without all the relevant facts, the Court of Appeal decision reads.
Justice Kit Toogood's High Court decision, the first of its kind under the Anti Money-Laundering and Countering Financing of Terrorism Act, ended Xiao's 20-year career with the ban from offering financial services.
The Court of Appeal judges attempted to get further details of Xiao's proposed defence, but without the assistance of an interpreter said "communicating with Mr Xiao about such complex matters was very difficult".
The judges, however, were not prepared to conclude Xiao's challenge has no prospect of success and said "there is a risk" that without the aid of Hunter he would not be given the opportunity to pursue a tenable appeal ground.
Xiao was the director and sole shareholder of Ping An, which is now in liquidation.
He earlier challenged the $5.3m fine and lost.