Lomax has been named on the bench for Tasman's Mitre 10 Cup match against Otago, with kick off at 4:35.
Waikato host Manawatu in Hamilton from 2:35.
Australian-born Lomax grew up playing rugby league in Wellington but switched to rugby union when his family returned to Canberra.
He was named the Australian under-20 player of the year last year and made regular appearances this season for the struggling Rebels.
Named in Wallabies coach Michael Cheika's original 48-man squad for 2017, he admits he faced a tough decision about his future.
"I grew up in New Zealand and as an aspiring rugby player the chance to play for a NZ Super Rugby club was too good an opportunity to turn down," he said.
"As a young prop I can't wait to get to the Highlanders, they have an awesome culture there and I just want to immerse myself in it and learn as much as possible."
Highlanders chief executive Roger Clark was impresses by the maturity of Lomax throughout negotiations and believes the hulking young front rower has the potential to go a long way in rugby.
New Highlanders head coach Aaron Mauger expects the youngster to make an impact.
"Clearly we see Tyrel as an exciting future prospect for the club," he said.
"A strong ball carrying prop, we think his game will benefit from our environment and he will add depth to our squad."
