The owners of New Plymouth's Pak'nSave have been fined nearly $30,000 after four workers suffered carbon monoxide poisoning.

Melody Holdings Limited pleaded guilty of failing to take all practicable steps to ensure the safety of the employees.

Four workers were rushed to hospital last year where they were treated for carbon monoxide poisoning, three ended up in intensive care.

On Friday Judge Allan Roberts released his reserved decision to fine the company $25,000 and ordered it to pay $1,000 in reparation to each of the workers.

The Labour Department's Taranaki Service Manager Brett Murray says the employees had a lucky escape. He says the incident highlights the potential dangers of poorly ventilated workplaces.