Former Boomers coach Brown had been roped for an Olympic cameo to replace Andrej Lemanis, who stood down after the side narrowly missed a medal at last year's World Cup.

It was hoped Brown's connection with Australia's impressive list of NBA products would be the missing link to lead them to a maiden medal at the 2020 Tokyo Games.

The coronavirus pandemic intervened though, the Games now slated for 2021 and Brown since losing his job at the NBA franchise headed by Australia's star man Ben Simmons, who had indicated his desire to play in 2020.

NBA boss Adam Silver has stated next year's season could run straight through the proposed July-August Games window, leaving NBA players and coaching staff with an eye on the Olympics treading water.

Without a new job confirmed, Brown said on Tuesday he had no choice but to back out of his Boomers' duties.

"Whilst I have a deep and long-standing passion for Australian Basketball, I am currently unable to commit to coaching the Boomers at next year's Olympic Games," he said.

"The uncertainties around the direction of my professional future unfortunately mean that I cannot commit to the time and preparation that this job deserves and requires.

"The difficulties around travelling internationally with my family during the pandemic have also contributed to my decision.

"It is important for me to give Basketball Australia, the coach, and players, the necessary time for a full and thorough Olympic Games preparation in the event that the Games do proceed."

He said he would help Basketball Australia in their search for a new coach.

If the NBA season does run uninterrupted through the Olympics it's understood players would need to be pardoned by their NBA clubs to compete.

While the likes of talisman Patty Mills and key pieces Joe Ingles, Matthew Dellavedova and Aron Baynes have expressed Olympic gold is a priority, it complicates matters for All-Star Simmons, who has not played for Australia since he was a teenager seven years ago.

Issues will also arise if players are not satisfied it is safe to play in Japan, or if they don't feel secure enough within their club to depart for national duties.

Basketball Australia will hold their breath until the NBA schedule is announced before seeking commitments from players, but have already begun their search for a coach.

"Basketball Australia is naturally disappointed that Brett is no longer able to commit to being the Boomers head coach for the delayed Tokyo Olympics but we fully understand Brett's situation, and appreciate his candidness when informing us of the decision," BA CEO Jerril Rechter said.

"The COVID-19 pandemic is creating a challenging environment for all sports in which to operate.

"The Tokyo Olympics is an important event for Basketball Australia and our male athletes, as collectively we believe the Boomers have an excellent opportunity to claim their first ever Olympic medal."

Australian Associated Press