More than half a dozen parishioners voiced their wish to keep their pastor, and most - including Mr Jang - left the service in protest before Mr Christian could make the announcement.
Church deacon Mrs Hee Sook Cho said: "We trust Rev Jang but we don't trust the Presbyterian Church."
Many also took offence that a summary of the complaints hearing committee's decision was circulated before the announcement.
The summary contained sexually explicit details, including the nature of the acts, where they happened and how often the deeds of misconduct were said to have occurred.
Retail worker Jo Park, 31, was in tears after the announcement and felt the church's action was "overkill".
"It's unfair not just to Rev Jang and the congregation, but also the complainant ... " Ms Park said.
The complainant cannot be named for legal reasons.
A Presbyterian Church disciplinary hearing found Mr Jang guilty of grave impropriety, sexual misconduct and physical, verbal and emotional abuse.
Congregation spokesman Nathan Jang said the parish council was looking at all avenues and options, including suing the Presbyterian Church for defamation, for the way it conducted yesterday's announcement.
Mr Jang told the congregation during the service that he would continue to lead them as a minister of the Korean Presbyterian Church Abroad, which did not fall under the jurisdiction of the local Presbyterian order.
But Mr Robinson said Mr Jang had not gone through the proper process to be transferred to the Korean church, and had done so without the approval of the presbytery.
"Regardless of any denomination Jang indicates he is now affiliated with, he has been found guilty of gross misconduct, and accordingly is not considered a minister in good standing," he said.
"He is barred from participating in any ministerial or pastoral duties within any Presbyterian or Uniting congregation in New Zealand.
"Should he ignore the ruling to cease and desist all pastoral and ministerial responsibilities in relation to his current congregation, we will take the necessary steps to remove him," Mr Robinson said.