The judge in the South Canterbury Finance trial has released his reasons for dismissing the defence's application to have him thrown off the case.
The failed finance company's former chief executive, Lachie McLeod, and former directors Edward Sullivan and Robert White, face 18 fraud charges at the High Court in Timaru.
The charges, brought by the Serious Fraud Office, include theft by a person in a special relationship, false statements by a promoter, obtaining by deception and false accounting.
On Monday, defence lawyers argued that Justice Heath may be potentially biased towards the Crown because of a comment made by SFO director Julie Read.
They said Ms Read was heard at a conference Justice Heath was also at, as saying the office was fortunate to have him presiding over the case.
The lawyers said based on that, the judge's impartiality could be called into question by a reasonable lay person.
Justice Heath said on Thursday that Ms Read's comment was unfortunate, but just good manners. He said there could be no bias through association because he had only just met Ms Heath.