Fonterra has been ordered to pay a former worker almost $40,000 for wrongful dismissal, after a shouting match erupted when he was accused of pulling a 'sickie'.

In 2022, Production Supervisor Steve Waite, who had worked for Fonterra for 27 years, called in sick with vomiting and diarrhoea.

Five others who were rostered on to the same production line were also away sick.

The team manager became suspicious and claimed she'd previously overheard discussion about staging a day off to disrupt production.

Waite became upset about his manager's scepticism, and request of a medical certificate, she had also contacted others, questioning their's and Waite's sickness.

There was an angry confrontation at a later meeting, and both accused the other of bullying and intimidation.

Waite was suspended, then fired for serious misconduct.

The Employment Relations Authority in Wellington has ruled Fonterra didn't investigate his actions thoroughly enough, and awarded Waite almost 40 thousand dollars in lost wages and compensation.

Fonterra declined to comment on the ruling, saying it doesn't comment on individual employment matters.