Wellington commuters faced lengthy drives home as trains were halted due to a tree falling on the tracks near Tawa.

There are big questions about the fragility of Wellington's transit network after a crash north of Wellington coupled with a cancelled rail service reduced traffic in the capital to a standstill.

The ripple effect of a crash between a bus and a truck on State Highway 2 north of Ngauranga interchange flowed through the CBD and reached the southern and eastern suburbs of Wellington yesterday.

Frustrated drivers voiced their anguish.

ASHTEN MACDONALD / Fairfax NZ. Wellington commuters faced long journeys home yesterday.

Daniel Eady tweeted "45 mins to get from Miramar to half way round Evans Bay, nice one Wellington traffic".

Cassidy Browne lamented "been stuck in Wellington traffic for over 40 minutes, still nowhere near the basin reserve..."

The crash debris several kilometres north of the city was eventually cleared and an afternoon of going nowhere finally ended for gridlocked commuters.

KIWIRAIL BACKLOG: A worker stands next to the fallen macrocarpa, highlighting how large an obstacle it was to remove.

Authorities praised the patience and behaviour of drivers during a"horrible day" on the roads.

However, many road users were questioning Wellington's capacity to deal with traffic if it only took a train disruption and a crash blocking one lane to grind the city to a halt.

Kat Singh tweeted "this is a result of an accident earlier. What's going to happen if it's a disaster?? We doomed!"

Yorrike said "It's bonkers. Northern motorway very congested due to earlier crash that it's made everything else stop. Plus, trains are out, so more cars".

Central police communications Inspector John Spence said it only took one crash to start backing up traffic and with the Kapiti Line out of service there would have been extra cars on the road.

Improving Wellington's transport options have been hot topics.

A flyover next to the Basin Reserve in Wellington - to ease congestion - was killed off last year and options are being canvassed for upgrading the motorway north of Wellington, so it can handle extra traffic from Transmission Gully and the Petone-Grenada highway.