The NBA has postponed the Boston Celtics-Miami Heat showdown due to health and safety protocols amid the coronavirus pandemic.

Sunday's contest was set to go ahead, despite the Celtics missing seven players – including star pair Jayson Tatum and Jaylen Brown – because of COVID-19 protocols, and nine in total.

But the NBA announced the postponement just hours before tip-off after a Heat player reportedly returned an inconclusive coronavirus test, leaving Miami without the required eight players to play due to contact tracing.

Heat guard Avery Bradley (health and safety protocols) had been ruled out of the game earlier in the day.

The Celtics were set to have the minimum eight players available against the Heat after Javonte Green, Semi Ojeleye, Grant Williams, Robert Williams II and Tristan Thompson were listed as outs pre-game.

Injuries had already forced Celtics pair Kemba Walker (knee) and Romeo Langford (wrist) to miss the scheduled meeting.

It comes as COVID-19 outbreaks impact the NBA following a coronavirus-hit 2019-20 campaign in the United States.

Eastern Conference leaders the Philadelphia 76ers were depleted for Saturday's loss to the Denver Nuggets after Seth Curry tested positive for coronavirus.

Contract tracing seriously impacted Doc Rivers' 76ers, who were without Curry, Tobias Harris, Matisse Thybulle and Vincent Poirier, paired with injures to All-Star duo Joel Embiid and Ben Simmons.

Philadelphia were only able to dress eight players against the Nuggets, though Mike Scott was unable to play due to a knee injury.

The Celtics own a 7-3 record in the Eastern Conference, ahead of last season's NBA Finals runners-up the Heat (4-4).