NZ Bus has considered stopping return night runs from Wainuiomata to Queensgate in Lower Hutt because drivers are terrified of being attacked.

Drivers using the route have been assaulted and abused, often by drunk or drugged youths, but incidents are rarely reported, according to an internal report written for NZ Bus's chief risk officer, Paul Hume.

The June 18 report follows an investigation into driver safety - launched after a driver was threatened with a knife on June 1.

"The risk of assault, both verbal and physical, is real," the report finds.

It notes an estimated 75 per cent of incidents of "threat, abuse and attack" were not reported by the company's Wainuiomata drivers because of a lack of faith that they would be listened to.

The report says drivers who don't bring torches to work are using their cellphones to find their way around the dimly-lit yard at the Wainuiomata depot.

The yard has also become a haunt for troublesome teenagers.

NZ Bus chief executive Zane Fulljames said the safety of staff and passengers was the company's first priority and a number of recommendations in the report had been implemented.

The report says the knife incident, which happened at 8pm on June 1, was just one of several that had occurred on buses between Wainuiomata and Queensgate in the past 18 months.

"As an employer, NZ Bus needs to provide a more programmed and systematic hazard management strategy to address the real risk of assault that exists within the Wainuiomata area - or consider ceasing the run," the report's author, Maeve Neilson, wrote.

Bus runs at risk of being axed were the 160 and 170 routes between Wainuiomata and the Hutt Valley on Wednesday to Saturday nights.

"This would have implications on the wider Wainuiomata community who rely on these services to return home from work in the Valley," Ms Neilson said.

The two main areas of risk for drivers were safety problems in the Wainuiomata depot and on-road dangers, including verbal and physical abuse and objects being thrown at buses.

Drivers reported the main verbal perpetrators as being drunk or drug-affected youths, many of whom were gang prospects.

"Threats often come in the form of a threat of assaults and weapons are often involved," the report found.

Drivers reported youths hanging around the depot at night, including one group of youths hiding in the women's toilets.

Mr Fulljames said meetings had been held with Hutt City Council and police on an approach to problem youth in Wainuiomata.

Discussions had also been held with Maori wardens.

Chief operating officer Shane McMahon said the issue was a community one.

"We do not want to see the services to Wainuiomata discontinued, but that is one option should we not see a reduction in the number of incidents. We would ask for assistance from the community in working to combat the actions of a few misguided individuals."

In April this year Lower Hutt bus driver Hermann Curry collapsed and died after chasing a youth he saw stealing the cash box from his bus. He was found at about 10pm by a colleague, lying on the ground of the Waterloo terminal next to his bus.

Two men, aged 17 and 20, were charged with the theft of the cash box, while a 15 and 16 year old were referred to Youth Aid.

CHANGES MADE

Changes made by NZ Bus since the knife attack:

Lighting has been improved significantly at the Wainuiomata Depot

The yard needs to be cleared of hiding places including fences, and trees

These recommendations are being worked on, and potholes have been filled

NZ Bus has been working with police and other community groups to reduce the risk to its staff

The alleged offender has been trespassed from all NZ Bus services

A security contractor is at the depot every night

At the beginning of the year NZ Bus improved its reporting system.

Serious incidents such as this will be investigated thoroughly to eliminate future risks

HOW DRIVERS KEEP SAFE

Existing strategies being used to improve safety:

Drivers who live in Wainuiomata tell "troublemakers" that they know their parents and will report misbehaviour to them.

Drivers take their cash boxes home instead of signing out at the end of a shift because they fear being attacked at the depot.

Drivers are, without approval, taking family members on the bus with them for support.

Maori wardens, police and volunteers have been invited to travel on the buses.

Drivers who encounter problems have sought backup assistance from other drivers using their radios.

The yardman drives around the depot like a security guard - offering assistance and calling police about problems.

- © Fairfax NZ News