New Zealander Brown has been tasked with transforming the Springbok attack since his arrival in 2024 and that has paid dividends in a largely dominant 2025 season that included a test record 43-10 defeat for the All Blacks in Wellington.
But he has never denied his desire to coach within the All Blacks set-up and will work under Rennie as an assistant from the 2028 international season onwards.
"Tony is a world-class coach who is highly regarded and consistently sought after by head coaches and teams around the world," New Zealand Rugby CEO Steve Lancaster said in a statement on Sunday.
"We know Tony is available after the 2027 Rugby World Cup and he’s made it clear he would love to be part of the All Blacks. This decision is simple, it’s about ensuring the best coaches return to New Zealand.
"For now, Dave and his coaching team are absolutely focused on what’s in front of them and we look forward to challenging ourselves against Tony and the Springboks in the coming months."
The Springboks and All Blacks clash in the 'Rugby's Greatest Rivalry' tour in August and September this year which will see the teams play three tests in South Africa and a fourth in Baltimore in the United States.
Springbok coach Rassie Erasmus was full of praise for Brown and said he will leave, when the time comes, with their blessing.
“Tony has made a remarkable difference, both on and off the field, and he has always been upfront with us about wanting to be closer to his family and about the All Blacks holding a special place in his heart, and we are genuinely delighted for him," he said.
Brown says he remains fully committed to the Springboks until the completion of the 2027 World Cup.
“My contract with New Zealand Rugby only begins in 2028, so there is still a long road ahead before that comes into play,” he said. “Right now, I am fully committed to the Springboks. What we are building and trying to achieve as a team over the next two years is my only focus.”
Former flyhalf Brown won 18 caps for the All Blacks between 1999 and 2001.
