Tonga-born MP Jenny Salesa said over her time in parliament she has asked principals and teachers what skills children need when they start school.
She said she had been told too many children of Tongan descent in New Zealand start school at the age of five speaking neither language fluently.
She has been stressing the message that learning Tongan can benefit their education overall.
"If they are are fluent in speaking the Tongan language, it is so much easier to build the English language on top of a language that they are already fluent in, that building all sorts of other skills is so much better and that's a message that I try to remember to tell our parents and the community whenever I speak."
Tongan Language Week is being celebrated in New Zealand this week.
There are just over 60,000 people of Tongan descent living in Aotearoa New Zealand, making them the third largest Pacific group in the country.
Photo: RNZ Pacific: Sela Jane Hopgood Jenny Salesa