The Manufacturing and Construction Workers Union says staff at EnviroWaste had earlier raised concerns about the type of recycling vehicle that was involved in the death of a 20-year-old worker this week.
Junior Hunt was crushed in his glass recycling vehicle's hydraulic lifting hoist on Tuesday morning, and died from his injuries in Wellington Hospital yesterday.
Union secretary Graeme Clarke said workers have told Envirowaste management the vehicles are unsafe.
"There are a number of issues with regard to working conditions that have been raised with the employer.
"My understanding is that the issues that these particular vehicles have been raised by employees with the company in the past but it's not something that people have at this point raised through the union."
Envirowaste's chief executive Garry Saunders said he was not aware of the concerns.