The 10-person protest highlighted issues around workplace safety and criticised amendments to the Health and Safety Reform Bill, which would exempt some small businesses from having health and safety representatives.
''The Bill stops short of ensuring protection for workers, regardless of the size of the business,'' Unions Otago convener Fiona Matapo said.
''We would want the legislation to be inclusive, and it clearly isn't ... In terms of setting up a healthy culture in the workplace, those [health and safety] representatives are quite crucial.''
Yesterday's protest vigil was the latest in a string of similar actions across the country over the past two weeks in protest against the Bill.
In a press release, Mrs Matapo said New Zealand's rate of workplace deaths was ''far higher'' than other similar countries.
She cited a Government-commissioned report that found New Zealand's proportional rate of workplace death was higher than those of both Australia and the United Kingdom.
''Every worker in New Zealand has the right to go to work and come home,'' she said yesterday.
Union member Judith Trevathan, whose uncle died in a workplace accident 13 years ago, was there.
''[My uncle] has always been a part of my life,'' Ms Trevathan said.
''It's strange to think that he went to work to do his job, and he died. And that shouldn't have been the case. He should still be in my life today.''
She went to the protest vigil because she said National was ''trying to dilute the Health and Safety [Reform Bill]''.
In an emailed statement, a spokeswoman for Mr Woodhouse said the minister was ''disappointed by the unnecessary anxiety [created]'' by union response to the Health and Safety Reform Bill amendments.
''The minister simply does not agree that flexibility for small businesses that are not high risk constitutes the watering down of health and safety reforms,'' she said.
''The Government has set a goal of reducing our health and safety toll by 25% by 2020, and is confident the reforms currently under way will address this.''
