The Auckland Tramways Union says the $2 million upgrade of bus stops along the city's Karangahape Road for the Rugby World Cup will lead to more assaults.
The union says a two-metre space between the upgraded shelters and motorway barrier will mean people can hide behind them and lie in wait for passengers, bus drivers or pedestrians.
It also claims the shelters will become pit stops for people to urinate.
Union president Gary Froggatt says the Ponsonby end of Karangahape Road is already a hotspot for trouble and being able to hide behind the shelters will only escalate problems.
Mr Froggatt says the upgrades were unnecessary and its just another example of wasted ratepayer money for the tournament.
Auckland Transport says the upgrades are needed as parts of the structures are collapsing.
A spokesperson, Sharon Hunter, says the shelters are made of clear glass and are well lit, so there should be no problems.
The area is already well policed and the authority will act on any trouble, if it arises, she says.