Police believe the body is that of 24-year-old Joanna Lam, but they say that will not be confirmed until formal identification has been completed.
Searchers have not seen any sign of her companion, 25-year-old Connor Hayes.
The couple from Ottawa were last seen at Fox Glacier on Sept. 10 in stormy conditions and parts of their rented van were found this week.
Tasman Police say the body was discovered around 2.30 p. m. Friday on the stretch of a beach between Haast and Knights Point, close to where the fuel tank from their vehicle was recovered earlier in the week.
Police believe the couple either drove over a cliff inadvertently or were swept off by a landslide.