"We're just sick and tired of this guy's [Winder's] management style and we think it's counterproductive," Kerr said yesterday.
"Frankly, we think Winders has to go."
A meeting last week of more than 100 members of the combined port unions, the Maritime Union of New Zealand and the Rail and Maritime Transport Union, decided unanimously to call on port management to abandon its aggressive approach to industrial relations at the port.
Workers raised concerns about alleged management bullying, Kerr said.
However, Winders' sinking-lid approach to staffing was exactly the wrong approach at the wrong time due to the stress at the maritime border facility, he said.
Winders said there was no ongoing sinking-lid policy at the port.
Everybody was just doing their jobs and the conversation between the two sides should not get personal, Winders said.
There had been tension as the port was trying to "right-size" and modernise its operations in light of its new collective employment agreement and after a particularly tough year.
Staff at the port responded brilliantly to the challenges of Covid-19 and the unions had been very good at working through issues with management as they arose on a daily basis early on in the global pandemic, Winders said.
But the loss of cruise ships at the port resulted in an $8million loss in revenue this year and there had been 21 jobs lost through staff retrenchments, he said.
Out of a workforce of 310 people, 12 people had taken early retirement and nine people had been made redundant.
It had not been an easy time, Winders said.
Next year, as the rate of change of port operations slowed and some of the changes were bedded in, the relationship would be improved, he said.
Before and after a meeting with the unions last week, Port Otago denied any allegations of management bullying at the port.
Port Otago said in a statement the unions had failed to substantiate their claims.