It'll be the biggest test for Wellington's new bus system today - with kids back to school and driver strikes.

The new timetables, routes and other changes will be put under pressure around the region as it's used to its full capacity.

Meanwhile, 50 bus drivers in the Hutt Valley will partake in industrial action to protest unlawful and dangerous shifts.

The drivers will only be working eight hours, instead of the 14 some are currently working.

48 services in the Hutt Valley will be affected - with Metlink saying it's possible other services in the region may be as well.

Greater Wellington Regional councillor Daran Ponter says the strike will put more pressure on the network.

He says it won't put pressure in the morning but towards the late afternoon is what they're anticipating.

However, Tranzit's managing director Paul Snelgrove doesn't believe it'll have a significant impact on the system.

He reckons they've got the drivers they need and are committed to getting everyone where they need to go.