Wisconsin's Supreme Court overturned the state's stay-at-home orders on Wednesday, as regions across the US grapple with the increasingly partisan decision of whether or not to reopen amid the coronavirus pandemic.

Americans across the country have staged anti-lockdown demonstrations and President Donald Trump has pressed for rapid steps to rekindle the devastated US economy before his tough re-election battle in November.

But public health experts, including the president's top medical advisor Anthony Fauci, have warned that loosening restrictions on public gatherings too early could trigger fresh COVID-19 outbreaks.

The Midwestern state's high court sided with lawmakers from Trump's Republican Party, who had challenged an extension of the quarantine imposed by Democratic Governor Tony Evers's administration.

Evers warned on Twitter that the decision risked undoing "all the work we have done and all the sacrifices Wisconsinites have made over these past few months."

Americans across the country have staged anti-lockdown demonstrations
Americans across the country have staged anti-lockdown demonstrations AFP / KAMIL KRZACZYNSKI

"It's a mess," he later told CNN. "I mean, I can't put it any other way."

While the state is not one of the hardest hit, it has still recorded more than 10,900 cases and more than 400 deaths.

The legal challenge was filed against Wisconsin Department of Health Services chief Andrea Palm and other officials, who had extended stay-at-home orders to May 26 even as the state relaxed some restrictions on business.

The state's Republican House Speaker Robin Vos and Senate Majority Leader Scott Fitzgerald said the ruling allowed "people to once again gather with their loved ones or visit their places of worship without the fear of violating a state order."

Asked whether relaxing shutdown orders was a partisan issue, Treasury Secretary Steven Mnuchin told FOX News Wednesday: "I hope it's not political, that would be terrible. I hope that all these governors care about the American workers, care about American jobs."