The campervan with two missing Canadians in it appears to have been swept off the Haast highway by a landslide and smashed to pieces in the raging flooded river.
A police search on Wednesday failed to find Connor Hayes, 25, and Joanna Lam, 24, who were last seen in Fox Glacier a week ago.
But wreckage of parts of their rental van was found down a steep gorge on the Haast River, close to where a large slip has closed State Highway 6 since last week.
Earlier the petrol tank believed to be from the couple's van was found more than 50 kms from where the pair are thought to have been swept off a cliff, into the Haast River.
Sixteen police and volunteers were involved in the search, using jet boats and a helicopter.
Police say they don't know whether the couple were in the vehicle when it left the road.
The Haast Pass has been closed by huge slips for the past week.
Meanwhile, the Transport Agency says it will review its decision to close part of the West Coast highway when it did.
The agency's West Coast area manager Mark Pinner says it closed the road last week due to flooding.
He says it was not aware of any slips at that stage.
Mr Pinner says the agency assessed the scene after the road was closed and found a slip, but could not find anyone needing help.
Searches for the bodies will continue on Thursday.
Haast police constable Rob Manera says the search is covering a wide area, but may be hampered by more bad weather forecast for the area.
"Living their dream"
Tamara Sagadore went to school with Miss Lam and they remained close friends.
She told Checkpoint Miss Lam was looking forward to starting a job as a radiographer at Nelson Hospital.
Ms Sagadore described the pair as very loving and living their dream.
She says Miss Lam had dreamed of coming to New Zealand.
"I spoke with Joanna right before she left for her trip about the beginning of August. She was just really excited to start her new job there. It'd been kind of one of her life goals to live there and it was kind of coming true in that regard.
"So she was really optimistic about moving there."
