Venezuelan opposition leader Maria Corina Machado said on Friday her country is starting a "true transition" to democracy and will become free with support from the United States and US President Donald Trump.

Trump however has sidelined Nobel laureate Machado and backed former vice president Delcy Rodriguez as interim leader of the oil-rich country following the January 3 US military operation that seized president Nicolas Maduro.

"We are definitely now into the first steps of a true transition to democracy," Machado said during an event in Washington, adding that this will have an "immense impact in the lives of all Venezuelans" as well as around the region and the world.

But Trump has said that Machado does not have enough support among Venezuelans, and opted to stick with Rodriguez, so long as she toes the line on US access to Venezuela's vast oil reserves.

Machado, 58, on Thursday presented her Nobel Peace Prize medal to Trump in a bid to win over the US president.

"He deserves it," she said. "And it was a very emotional moment, I decided to present the Nobel Peace Prize medal on behalf of the people of Venezuela."

It was not immediately clear if Trump – who said Friday that he and Machado will "be talking again" – kept the award following their White House lunch. The Norwegian Nobel committee says its prizes cannot be transferred. (AFP)