A government shutdown took effect just after midnight in the United States (US) as lawmakers in Washington failed to reach a consensus on legislation to keep the federal government funded.

Democrats are seeking concessions on reversing cuts to healthcare benefits and extending subsidies that form part of key healthcare legislation known as Obamacare.

Hundreds of federal workers will be furloughed and various services and federal agencies will be affected nationwide.

The minority Democrats have resisted giving Republicans the eight votes required to reach the 60-vote threshold required to pass the funding legislation in the Senate.

The last shutdown came during US President Donald Trump’s first term in 2018, the longest government shutdown in America’s history, lasting 35 days.

Democrats want to use the funding bill to reverse Republican cuts made to healthcare, which non-partisan groups say would reduce hundreds of billions of dollars to Medicaid spending and increase the number of uninsured by several million.

Republican Senate leadership has expressed openness to negotiate, but not on the stopgap funding measure.

Trump warned Democrats that a shutdown could lead to irreversible actions, including shutting down programmes and firing staff permanently.

The question now is which side will blink first.