The 33-year-old, who shared third place with compatriot Tim Slyfield in the men’s under 100 kilograms event at Glasgow 2014, recently retired after narrowly missing out on competing at the Rio 2016 Olympic Games. 

In his new role at Judo New Zealand, Koster will look to revamp the national "framework" with the view to ensuring success at the Tokyo 2020 Olympics.

"My goal is to get an Olympic medallist," he told Stuff.

Koster also has one eye on the 2022 Commonwealth Games, scheduled to be held in South African city Durban, where judo will return to the programme as a core sport having been omitted for Gold Coast 2018.

New Zealand claimed a total of five judo medals at Glasgow 2014, comprising two silvers and three bronzes.

Koster, however, is hoping to improve on that in six years’ time. 

"It gives us plenty of time because I've got a lot of framework I want to build," Koster added.

"Just creating some good pathways and platforms for these guys, because we did it all on our own accord and basically set our own career goals.

"We were self-coached and self-managed in the past.

"I want to try and eliminate that where possible in the future and basically give them [athletes] more support when they do go away."

Koster told Stuff a plan is in place to launch a judo academy in Christchurch next year, initially running out of the Canterbury Amateur Judo Club (CAJC) where he is continuing to coach.

"Even though we're a minor sport, we want to get a good hub of people working together so we can work towards international success," he said.

CAJC members accounted for 12 gold medals, more than any other club, at last month’s national championships in Auckland and Koster believes some of them have the capability to compete at Olympic level in the future.

Darcina Manuel, a women’s 57kg bronze medallist at Glasgow 2014, was New Zealand’s sole judo representative at Rio 2016.

She lost against Portugal’s Telma Monteiro in the second round having opened with a victory over Russia’s Irina Zabludina.