Mr Niu will be sworn in this week and is expected to start his four-year term in July.
Vuna Fa'otusia said Mr Niu was ideal for the job as he is one of the most experienced lawyers in the country a former President of the Tonga Law Society and former MP.
Mr Niu will join two New Zealanders on the bench.
Mr Fa'otusia is hoping to have an all-Tongan Supreme Court bench by 2020 and hopes that court proceedings will one day be conducted in Tongan instead of English.
