The Haast Pass will stay open tonight, protected by what the Transport Agency says is the most complex rock fall protection system in Australasia.
The key tourist route on State Highway 6 had been closed nightly since a major slip in September last year.
The slip at Diana Falls, near the Gates of Haast, brought down 40,000 cubic metres of rock - on the same night another slip nearby killed two Canadian tourists.
The Transport Agency's new three-net protection system above the road cost $9 million.
Spokesperson Pete Connors said the protection was strong and able to stop a 16-tonne rock travelling at up to 90km/h. He said the section of road was now as safe as any other.
Barriers 'could reduce risk'
A consultant to the Transport Agency says lockable barriers could be considered for the Haast Pass to prevent drivers getting into dangerous situations.
The suggestion was made at an inquest in Greymouth yesterday into the deaths of the Canadian couple who drove into the pass during a storm as road closure signs were set up behind them.
The inquest which was held in Greymouth looked at the circumstances which led to the death of tourists Connor Hayes and Joanna Lam when a landslide swept their campervan into the Haast River in September last year.
Edward Guy, a civil engineer and consultant to the Transport Agency, said lockable barricades could be set up in unsafe areas to stop people getting into dangerous situations in the area between Burke Flat and the Haast Pass summit.
Mr Guy said the area was prone to flooding, snow, slips and debris.