A Taranaki woman on a learner's licence drove the wrong way in the fast lane of the Wellington motorway at night, narrowly avoiding a head-on crash.

Robyn Martin, 36, of New Plymouth, saw a sign saying "Wrong Way" as she drove on to the motorway but said she thought it was faced in the wrong direction.

She ended up clipping another car, the collision ripping off a wheel from her car and lodging it in the front of the other car.

In New Plymouth District Court yesterday, Martin pleaded guilty to dangerous driving.

The police summary reveals Martin was heading home to Taranaki from Lower Hutt about 3.30am on April 11 when, heading north, she got to the State Highway 1 Whitford Brown Ave traffic lights and drove into the southbound motorway's fast lane.

She was travelling between 80kmh and 100kmh on a slight bend when she saw a car coming directly towards her.

Both drivers took evasive action to avoid a head-on collision, and their vehicles glanced off one another. However, the left rear wheel of Martin's car was ripped out and lodged in the front of the other driver's car.

When police arrived, she said she was confused by the layout on a road she didn't know.

She had two passengers in her car while the other car had four.

Julian Hannam, for Martin, said it was fortunate nothing worse had happened, and put the incident down to her lack of experience of big-city driving. She was out of her depth at night and "utterly and completely lost".

Her car was a write-off and it was likely the insurance company for the owner of the other car would pursue her for more costs, Mr Hannam said.

Judge Max Courtney said it was clearly dangerous driving – but at the lower end – when she was headed down the wrong lane on the motorway late at night.

Fortunately there had been no serious injuries.

She should have been alerted by the 'Wrong Way' sign but the judge accepted that she was confused.

Martin was fined $500 plus court costs and disqualified from driving for six months.