An Auckland bus driver was pulled out of her bus by three hooded men who punched and kicked her to the ground.
FIRST Union transport organiser Emir Hodzi said the driver was driving her usual night route in Mangere on July 4 when the attack took place.
The woman had since seen her attackers and alerted the bus company to it.
Hodzic said serious driver assaults occurred only a couple of times a year but the incidents highlighted the need to have more robust safety procedures.
A FIRST Union survey in October showed more than half of bus drivers reported being abused or assaulted by passengers while on the job and noted the more minor assaults were often not reported.
Hodzic said more needed to be done to keep drivers safe.
"We know they have panic buttons and some safety protocol but we don't feel it goes far enough.
"Both bus companies at Auckland Transport actually have a responsibility here to get together and decide on how to increase security for bus drivers. It's also evident there's a lack of security staff at bus depots," he said.
"We would like to assist Auckland Council and bus companies in coming up with more detailed guidelines and for bus companies to be more proactive in responding to issues when they do arise. Accidents and assaults really affect drivers' mental health."
A police spokesman said they were investigating the incident.
"Police have reviewed CCTV footage and we are following strong lines of inquiries," he said.
No charges have been laid.