They are now trying to recover the bodies of Connor Hayes, 25, and Joanna Lam, 24, along the west coast of the South Island.
The couple from Ottawa were last seen Sept. 10 in stormy conditions and parts of their rented van were found this week.
"Our effort now is a recovery operation, and weather permitting, we will continue searching until we have exhausted all reasonable possibility of finding these people," West Coast Police Area Commander Insp. John Canning said in a release posted on the Tasman Police website.
The couple had been touring the country and Lam was due to start work Monday as an imaging specialist at Nelson Hospital.
Police believe they either drove over a cliff inadvertently or were swept off by a landslide.
Thursday's search was assisted by a helicopter with heat-seeking equipment and also a specialist search dog on the ground.
Police said more debris from the wrecked van had been located and the vehicle's chassis had been recovered from the Haast River.