The outgoing U.S. Energy Secretary Rick Perry has said he does not believe that U.S. President Donald Trump will be formally impeached, even though political opponents are clearly determined to "harm" him.

Trump is denying allegations that he tried to pressure Ukraine to investigate Joe Biden and his son Hunter in an effort to damage Biden's 2020 Democratic presidential bid.

Now, and for only the fourth time in history, the House of Representatives has started a presidential impeachment inquiry. House committees are trying to determine if Trump's call to the president of Ukraine, Volodymyr Zelensky, violated his oath of office by asking a foreign country to investigate a political opponent.

Perry, who is on a trip to Dubai, told CNBC's Hadley Gamble on Saturday that he didn't think Trump would eventually face articles of impeachment.

"No, not at all. This is as a big a 'chasing the ghost' as I've seen before," said Perry.

"People so dislike this president in a political way that they will spend whatever it takes, even to the point of giving up their own reputations, to try to harm him," the energy secretary added.

Perry said he has been in many meetings with Ukrainian officials and the real goal was always to try to give the country access to energy which didn't come from Russia.

Rudy Giuliani — the president's private attorney — has taken a lead role in communications with some officials in Ukraine. When asked if Giuliani had become a political liability to Trump, Perry said "I don't know," before adding that it is often important to take advice from outside of political administrations.