The rear wheels and chassis of a van Connor Hayes, 25, and Joanna Lam, 24, were renting were spotted by a police officer down a bank this morning.
The pair were last seen at Fox Glacier on the afternoon of September 10.
Miss Lam was due to start working at the radiology department at Nelson District Health Board on Monday. A spokeswoman said the board's chief executive Chris Fleming was "very concerned" about her disappearance.
Police said the wrecked van parts were found in a gorge off the Haast Pass road at Haast Gates on the West Coast.
They were located about 80 metres down a bluff in the Haast River. The body of the vehicle and the engine had not yet been found.
A massive slip at Diana Falls closed the road - State Highway 6 - between the Gates of Haast Bridge and Haast Pass Summit last Wednesday.
"At this stage police do not know whether Miss Lam and Mr Hayes were in the vehicle when it left the road," police said.
"A police crash investigator and photographer are at the scene and searching will resume tomorrow."
Searchers were planning to make their way up the Haast River on foot and in jet boats at first light. A helicopter would also be used to search the area.
A Haast resident travelling the Haast Pass highway on Tuesday said they saw an unknown campervan ignore the road closure warnings and drive up the valley. The resident turned around after seeing the signs.
Efforts by the Transport Agency to clear and reopen the road have been hampered by bad weather. Teams were hoping to continue their work tomorrow, but were wary of poor weather forecast for Thursday.
The Transport Agency was aiming to have one lane on the road opened by Friday, they said in a statement.
- additional reporting Greymouth Star
