One in two poker machines will be deactivated and gamblers will not be allowed to sit side by side at Australia's two largest casinos under new social-distancing rules aimed at arresting the advance of the coronavirus.

But unlike other global casino giants which have temporarily closed their venues in response to the fast-moving outbreak, including in Las Vegas, both Star Entertainment and Crown Resorts will keep their casino doors open.

James Packer-backed Crown Resorts is bracing for a hit to its profits due to the spread of coronavirus in China. Credit:Joe Armao

The new social-distancing measures at Sydney's The Star and Melbourne's Crown – which come after health authorities at the weekend expanded guidelines to urge people to remain 1.5 metres from each other – include deactivating every second poker machine and electronic table game, enforcing distancing at seated gaming tables between players and limiting the number of players at each stand-up table to five.

Bars, nightclubs, restaurants, ballrooms and conference facilities will be limited to 450 people at Crown's casino and 499 people at The Star.