Gamblers and revelers flocked to Las Vegas as the city increased its casino capacity from 35 per cent to 50 per cent.

Sin City made the move on Monday when Nevada's governor, Steve Sisolak, signed the "Roadmap to Recovery" plan. The plan sets guidelines for the state's eventual full reopening.

Despite the rule going into effect on Monday, visitors descended upon Las Vegas in droves.

According to the Las Vegas Review-Journal, the flurry of people made the city near indistinguishable from any other year, save for the face masks and signs urging people to social distance.

“I took a few pictures to send to my son in Chicago, and I said, ‘I can’t believe there are this many people out,’” Las Vegas resident Laura Amendala, 55, told the paper. “I couldn’t even get into the Bellagio parking lot to see the botanical garden. It was filled to capacity.”

Social media posts from the weekend show crowds of people walking the city's streets, sometimes in dense, shoulder to shoulder clusters. Most of the visitors appear to be wearing masks, and those who were not appeared to be approached by casino staff to insist they cover their mouths and nose.

Thus far, Nevada has had 299,287 coronavirus cases, and 5,118 known deaths.

The city, known for its many casinos, reopened just as the $1,400 payments from the $1.9t coronavirus stimulus package began to land in American's bank accounts.

Andy Hooper, a restaurant owner in the city, told the Las Vegas Review-Journal that while his serving capacity likely would not be affected, he believed the move would shift visitor's moods.

“It won’t affect us as a whole for getting more people into the restaurant because of the distance rules,” Mr Hooper says. “But it is a psychological thing. I think that people will feel more relaxed. I think that the times that we do have available for guests to come in to dine are going to be extended.”

The state also expanded event capacity, now capping large, scheduled gatherings at 250 people or 50 per cent of a venue's capacity, whichever is less.

The state limited building capacity to 25 per cent last November. In February the state increased that capacity to 35 per cent.

If coronavirus cases continue to decline in Nevada, the state indicated it would allow further reopening beginning 1 May.

Restaurant, bar and hotel employees were authorised on 11 March to book vaccination appointments.