Simply titled Jonah, the project received $5.4 million in taxpayer funding from NZ on Air.
The two 90-minute features will tell the "phenomenal story of the boy from Tonga via NZ who took the rugby world by storm". It will air on Three next year.
Standing 1.98m tall, Veaila, 21, has the right physique to play the former All Black, who became the youngest player to debut for the national team at 19 in 1994.
Veaila is a rookie actor and this is his first major role. His credits to date have been with productions at New Zealand Drama School, Toi Whakaari, where he completed his final year last month.
This is the second time Lomu has been portrayed on the screen. Wellington rugby player Zak Fe'aunati played Lomu in the 2009 film Invictus.
Starring Morgan Freeman and Matt Damon, it's about Nelson Mandela's first term as the South African President who unites the apartheid-torn land by having their national rugby team host and win the 1995 Rugby World Cup.
This tournament introduced Lomu to the world when he thrilled fans by trampling over England fullback Mike Catt on the way to a memorable try.
Lomu played 63 tests, scoring 37 tries on the wing and retired in 2002. He became a long standing international ambassador for the game until his death from a heart attack in 2015, aged 40.
He suffered a kidney condition most of his adult life and had a transplant in 2011. He was on the waiting list for another, when he died.
The drama is produced by Great Southern Television. Chief executive Philip Smith told Stuff in July that the drama would tell "the real story. Not the cliches".
"We are the first biographers to talk to everyone," he said.
"It will be confronting but an incredible ride at the same time, just like his life. And he will definitely stomp over Mike Catt."
Great Southern Television collaborated with Lomu's wife, Nadene to bring the untold story to the screen.
The mini-series will screen in the build-up to next year's Rugby World Cup.
Photo Aspiring Tongan actor Mosese Veaila