The former finance manager of Waiwera Water Thermal Resort has launched a personal grievance claim believed to be worth several hundred thousands dollars.
The resort is owned by intensely private Russian magnate Mikhail Khimich.
Former chief financial officer Roger Mackereth left Waiwera Water abruptly in May, after nearly 15 years with the company.
The Employment Relations Authority received a complaint this month.
Mackereth said he'd have to speak to his lawyer before talking to the Herald on Sunday.
"There has been a lot going on but the lawyers are fighting it out."
Waiwera Thermal Resort general manager Alexander Yaroshevich described the legal action as unfortunate.
"That was a bit misfortunate, the situation with Roger, but there is not much I can say."
Yaroshevich said the company had been restructuring since Khimich bought 60 per cent of it last year.
His application to purchase the remainder of the company was still being processed.
He refuted any suggestion the company favoured Russians in senior positions.
"We just recently hired the new resort general manager who is as Kiwi as kiwifruit," he said.
"I have said I don't want to have more Russians here.
"We need people who can do the job."
Yaroshevich said Waiwera employed staff from South Africa, Fiji and the Philippines.