Emergency services were alerted shortly before 5pm yesterday that a man had fallen from a rock into the Rob Roy Stream and had failed to resurface, police said in a statement.
A search team was immediately sent to the area but he was unable to be located.
The search resumed this morning about 8am.
Wānaka search and rescue chairwoman Raewyn Calhaem said DOC has closed the popular walk to Rob Roy Glacier while the search continues.
She said the conditions were overcast and Search and Rescue have a "swift water team at the site".
Sergeant Darren Cranfield said that "conditions are good'' and they were able to finish searching the canyon area for today, and will resume searching below that tomorrow at 8am.
He confirmed that the missing man is an ''overseas person'', however they have not yet contacted the next of kin and cannot release any more information regarding the circumstances of the call they received.
In regards to the track closure he said: "We will probably get it reopened by the Sunday morning or tomorrow afternoon".
