New Zealand Rugby’s judicial committee has ruled that Walker-Leawere will be banned for three months if he does not complete the programme.
Drug Free Sport New Zealand chief executive Nick Paterson supports the “athlete-centred approach”.
“We don’t believe that cannabis is performance-enhancing,” said Mr Paterson.
“Getting Mr Walker-Leawere substance of abuse support and back into sport after serving his sanction is the most practical outcome and supports long term athlete health and wellbeing.
“We’ve advocated to remove cannabis from the Prohibited List for over 15 years and will continue to do so.
“However, while cannabis remains on the prohibited list, the best approach to avoiding a positive test is to avoid using it.”
The lock told New Zealand Rugby he had met with non-rugby friends and smoked marijuana to “wind down” several days after the match in Fiji.
Walker-Leawere hails from Ruatoria and is the son of Kele Leawere who captained Fiji at the 2007 Rugby World Cup in France and scored a try in his country’s victory over Wales.
He played for the Gisborne Boys’ High School First XV and for the New Zealand U20 side which won the world title in Georgia in 2017.
He came on as a reserve for Poverty Bay in a Heartland Championship match against Thames Valley in 2015 and moved to Wellington the following year.
Walker-Leawere has played 54 matches for the Hurricanes, 22 for Wellington, 33 for Hawke’s Bay where he currently plays in the National Provincial Championship, and 10 for the Maori All Blacks.