A project to set up "quarantine motels" in the US coronavirus epicenter of Washington state has infuriated local residents who fear they will be exposed to a high risk of infection.

More than half of all US novel coronavirus deaths so far have struck in King County, which encompasses the city of Seattle. The region has suffered 43 fatalities.

With the entire northwestern state going into lockdown Monday -- bars, restaurants, gyms and museums are all closed -- officials have moved to fill four properties bought to house those unable to self-quarantine.

These include the homeless, people with mental health issues or those living in multi-generational households worried about exposing elderly relatives.

Officials in Washington state have moved to fill four properties bought to house those unable to self-quarantine
Officials in Washington state have moved to fill four properties bought to house those unable to self-quarantine AFP / Michelle WALLARD MARTIN

The scheme is intended to relieve hospitals as resources grow increasingly stretched by the pandemic.

But Maddy Clemons, who works at coffee shop Bri's Beans opposite one motel in Kent, said she fears bringing the virus home to her two-year-old if customers pass it on to her.

"It worries me that (residents) could just leave the motel and walk up here to grab a coffee," she said, adding that she only learned about the quarantine site from a television crew who came to report on the plan.

"I'm looking for new employment, I'm so worried about it."

Soon after the motel opened, a homeless person who had not yet learned their coronavirus test result left the property, stole goods from a 7-11 convenience store and boarded a public bus.

Kent mayor Dana Ralph has called for heightened security including physical fencing
Kent mayor Dana Ralph has called for heightened security including physical fencing AFP / Michelle WALLARD MARTIN

Kent mayor Dana Ralph has called for heightened security including physical fencing, writing on Facebook: "My fears for this facility have come true. The things I predicted would happen now have happened."

On Monday, Governor Jay Inslee moved to reassure residents.

"We can all understand why people would be anxious if one person walked away -- who turned out to be not positive by the way -- into our neighborhoods," he said.

"Those aren't the people you need to be afraid of or concerned about. You need to be concerned about your best friend or your family."

But two employees in a Denny's restaurant, also across the street from the motel, expressed fears.

The scheme is intended to relieve hospitals as resources grow increasingly stretched by the pandemic
The scheme is intended to relieve hospitals as resources grow increasingly stretched by the pandemic AFP / Michelle WALLARD MARTIN

"If I get sick, I'm suing," said one employee, asking not to be identified.

Currently, quarantine at the sites is voluntary. Residents will be provided with food and monitored by health professionals.

Though it has space for 85 people, the Kent motel was empty Monday. Officials warn the virus may not peak for eight weeks.

King County communications director Alex Fryer said the property was bought for several reasons: each room has separate ventilation, doors all open to the outside and it was for sale as the crisis began to escalate.

But the emergency purchase was immediately controversial. City mayor Ralph took King County to court but lost.

Treasure Nazario, 27, who often shops at the 7-11 opposite the motel, called it "suspicious."

"I have four kids. I have a baby. It's scary. It seems underhanded," Nazario said.

Inslee has called for people to show "level-headed and community-minded" responses to quarantine sites in their areas.

But some residents of White Center -- home to large Asian and Hispanic populations, far from the main outbreak hub -- say the decision for their community to host another quarantine site was racist.

"Why would you put it inside our neighborhood among so many schools and homes?" asked health worker Isabelle Kihano, in Spanish, at a county meeting.

King County commissioner Jeanne Kohl-Welles said there "was no time" for a detailed review.

"Speed is paramount," she added. "We're in an unprecedented crisis."