Mr Macpherson acknowledged the funding application was unusual because the family of patients in such situations were normally required to meet their own legal expenses, while hospital authorities had costs met by the taxpayer.
He said the family regard such a situation as "grossly unfair to already grieving families, who are then forced to compete on a completely uneven playing field".
"We do not see why the people who were legally responsible for Nicholas' care when he died should get their legal bills fully funded by the taxpayer, while the family has to pay 100 per cent of its costs incurred while trying to establish the truth about what happened," Mr Macpherson said.
"We are asking in our presentation for legal funding to match the costs of the DHB's own legal spending, no more, no less."
Mr Macpherson, his wife Jane Stevens and one of Mr Stevens' brothers would appear at the board's public meeting at 1.30pm today to present their case.