"Maori is endangered. I 100% support making Maori compulsory.
"This country has a wonderful opportunity to make people bilingual.
"There are languages dying around the world on a constant basis-it doesn't have to happen with Maori," Dr Sweetnam Evans said.
Maori Language Week was a positive event, but she thought the compulsory teaching of Maori in schools should be phased in to keep the language alive.
During her earlier education in South Africa, she had to be fluent in at least two languages, Afrikaans and English, to complete her secondary school studies.
South Africa had 11 official languages and every South African learned more than one language.
International research highlighted many reasons for learning a second language and keeping threatened languages alive.
"If you learn a second language early it increases and improves your general academic achievement."
Dr Sweetnam Evans co-ordinates the linguistics programme at the Otago department of English and linguistics.
The Green Party this week called for the teaching of Maori to become a compulsory part of primary schools' core curriculum by 2025, and Prime Minister Jacinda Ardern says more teaching resources should be provided to ensure pupils can learn the language.
Dr Sweetnam Evans rejected any claims that learning a second language would undermine the learning of pupils' first language.
Extensive international research showed the opposite was true, she said.
"There are absolutely no negatives; there are only positives."
There were clear educational benefits for individual pupils, for schools and for society in general when pupils learned more than one language.
Learning a second language also helped provide insights into the first language, and there was evidence that becoming fluent in a second language helped people learn a third or further languages, she said.