US senators have passed the final Senate version of a historic healthcare reform bill.

The bill aims to cover 31m uninsured Americans and could lead to the biggest change in US healthcare in decades.

President Barack Obama welcomed it as offering “real and meaningful” reform, saying it was the most important piece of social legislation since the 1930s.

However, it must still be reconciled with more expansive legislation passed by the House of Representatives.

The process of reconciling the two bills is expected to begin in January and will require further tough negotiations.

Once that has been done - and the process could still be derailed by last-minute changes of heart among senators - Mr Obama will be able to sign the measure into law.

“We are now finally poised to deliver on the promise of real, meaningful health insurance reform,” the president said in a news conference following the Senate vote.