US President Donald Trump has threatened to use an executive order to cut off some of the key elements of former President Barack Obama’s signature health care law, the Affordable Care Act.

According to US media reports, Trump is likely to draft details of an order that would instruct three key agencies to rewrite a series of regulations that impact health insurance.

The new order is expected to exempt association health plans - small businesses that band together to purchase coverage for all their employees - from the need to comply with principle elements of Obamacare, reports indicated.

Trump has repeatedly failed to push legislative efforts to repeal Obamacare.

On Tuesday, Trump tweeted that he would be using the power of the pen to give people great health care since Congress did not act.

Since Congress can’t get its act together on HealthCare, I will be using the power of the pen to give great HealthCare to many people - FAST, Trump said.

Last month, the so-called Graham-Cassidy legislation, named after Republican Senators Lindsey Graham of South Carolina and Bill Cassidy of Louisiana who sponsored it, was the Republican Party’s new hope to replace Obama’s Affordable Care Act.

Trump had promised during his election campaign, and later as president, to introduce a new health system that benefits more Americans at a lower cost.

However, the Republican Party has failed to unite behind previous initiatives like the Better Care Reconciliation Act (BCRA), despite having a 52-48 majority over Democrats in the 100-member Senate.