Republican senator Rand Paul has said his own party's actions are "unacceptable" after he claimed it was holding a congressional Obamacare repeal-and-replace bill "under lock and key".

Mr Paul called the repeal of the Affordable Care Act "the biggest issue before Congress and the American people right now" and demanded House leaders release the text of the bill.

Bloomberg reported the bill was being kept in a dedicated reading room and that it will only be available for viewing by members of the House Energy and Commerce panel from Thursday. No one will be given copies to take away in a bid to avoid leaks, it said.

Mr Paul said: "I am heading to the secure location where they are keeping the House Obamacare bill. I will demand a copy for the American people.

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"What is the House leadership trying to hide? My guess is, they are trying to hide their 'Obamacare Lite' approach.

"I call on them to make this process transparent and to let the sunshine in. Today."

White House reporters said politicians were hunting down the bill but that it had been moved from its initial location.

Support for Barack Obama's flagship policy has reached its highest level since it was introduced in 2010, weeks after President Donald Trump signed an executive order to kickstart the dismantling of the healthcare law. It now enjoys majority support—at 54 per cent—for the first time.

The Affordable Care Act insures some 30 million Americans, although part of the current administration's policy is to "repeal and replace" it.

Since its inception, the act has divided opinion, with roughly as many Americans approving as disapproving of the law as recently as December.