The book looks at Pasifika links to New Zealand and what the future may hold, covering topics including politics, sport and the economy.
It's publishing comes as New Zealand's Tongan community continues to celebrate the Island nation's huge Rugby League World Cup campaign, where they came agonisingly close to securing a spot against the Kangaroos in last night's final in Brisbane.
The Tonga team were headlined by star ex-Kiwis and Kangaroos players including Jason Taumalolo, Andrew Fifita and Manu Vatuvei.
Fifita chose to represent Tonga instead of Australia and Sio Siua Taukeiaho, Taumalolo, Vatuvei, Manu Ma'u and David Fusitu'a turned down the chance to play for New Zealand.
In the book, Salesa argues that while Pasifika talent has made a huge impact on the field in both rugby codes in New Zealand, off the field they do not have a huge representation in coaching and administration roles.
"The key talents in and drivers of the professional rugby industry are often Pacific workers ['players']," Salesa writes.
"Even across the Tasman, around 40 per cent of the Australian National Rugby League competition are Polynesian."
Boards of the Blues, Chiefs and Warriors ethnically diverse as a 1980s Remuera Rotary club.
Salsea points out Auckland's three professional rugby and league teams — the Warriors, the Blues and Chiefs — are chock-full of Pacific players. It has been this way for two decades.
He said there was nothing like that type of diversity in management and executive positions — "the roles that are far more durable, not susceptible to injury, selection or intense public scrutiny, and which pay as well as some players' salaries".
Although this year's Chiefs, Blues and Warriors coaching team featured coaches of Maori or Pasifika descent, Salesa said that had been "unprecedented".
But across the board table and other administration roles, cultural diversity was lacking.
"The boards of these three teams [and their unions] are, in general, about as ethnically diverse as a 1980s Remuera Rotary club," he wrote in Island Time.
"The contrast between the thoroughly Māori and Pacific teams, and their colourless boards, is quite astonishing."
New Zealand Rugby League were approached for comment but declined.
Media managers for the Blues and Chiefs were unable to respond before publication.
But New Zealand Rugby CEO Steve Tew acknowledged there were "gaps in diversity in rugby management and governance right across rugby".
"That's pretty plain for anyone to see," he said.
"One of our short-term priorities to be delivered by 2019, is to increase Maori and Pasifika participation and create performance pathways."
Tew said there was no quick fix but it was an issue NZ Rugby was committed to resolving.
"We would love to see more Pasifika people contributing at higher levels of rugby administration.
"Many already provide important leadership in professional coaching roles, and we also support many of our Super Rugby coaching staff who regularly join Pacific unions for their end of year tours. Our focus now needs to be on creating opportunities that encourage that participation at a governance level."
Salesa writes that rewards were "obvious for a few high-performing, world-class individuals".
"Yet at the same time as the industry substantively rests on Pacific players' labour, these players, their families and their communities capture only the smallest proportion of the value of what they create," he writes.
"Pacific players are the labourers of the sports industry, bearing the risk, the injuries, the concussions and their aftermath, but have virtually no control or leadership in the industry, and no ownership of the enterprise."
"Like athletes in other collision sports, rugby futures are 'dangling by the sturdiness of their ACLs'."
● Island Time is released on Friday. For more information, visit here.
