Former U.S. vice-president Dick Cheney kicked off a media tour Tuesday to promote his memoir by insisting the decision to invade Iraq in 2003 was "sound policy" and didn't hurt America's reputation abroad.

Former U.S. vice-president Dick Cheney defended his memoir as a `balanced account` of his political life, despite former colleague Colin Powell claiming he was taking `cheap shots` in the book.

"I don't think that it damaged our reputation around the world," Cheney said of the invasion in an interview with NBC's Today show.

"I just don’t believe that. I think the critics at home want to argue that. In fact, I think it was sound policy that dealt with a very serious problem and eliminated Saddam Hussein from the kind of problem he presented before."

Cheney, viewed by many critics as one of the most powerful and divisive figures in U.S. political history, also suggested the invasion and subsequent removal of Hussein in Iraq led Libyan ruler Moammar Gadhafi to "get religion" and halt his regime's pursuit of weapons of mass destruction.

"What would’ve happened this week if Moammar Gadhafi had still been in power with a nuclear weapon in Libya?" Cheney told NBC host Matt Lauer.

"Would he have fled? I doubt it."

Cheney also made light of his controversial reputation when Lauer mentioned some of the labels applied to him during his terms as vice-president and asked him whether there was something about his personality that inspired such animosity from his critics.

"You left out Darth Vader," Cheney quipped.

Waterboarding 'worked'

The second-in-command in George W. Bush's administration again defended waterboarding as a "safe, legal and effective" method of interrogation, despite the practice being condemned by human rights organizations and Bush's successor Barack Obama as torture.

Cheney said only "a handful" of extremist figures, such as accused al-Qaeda and 9/11 mastermind Khalid Sheikh Mohammed, were subjected to waterboarding, which simulates drowning by forcing water down a bound subject's nose and mouth.

"The fact is, it worked," he said, while noting those waterboarded were not American citizens. "We learned valuable, valuable information from that process and we kept the country safe for over seven years."

But Cheney said he would oppose the same technique being applied to an American accused of espionage abroad on the grounds that the United States has obligations to "do everything we can to protect our citizens."

Anger over Bush's pardon refusal for Libby

Cheney, currently on a promotional tour for Tuesday's release of his memoir In My Time, has previously predicted "heads are going to be exploding all over Washington" over the contents of the book.

The memoir reveals some details of rifts between members of Bush's team of advisers, as well as anger with Bush over his refusal to pardon Cheney's chief of staff, Scooter Libby, who was convicted of perjury and obstruction of justice as part of the investigation into who leaked the name of CIA agent Valerie Plame.

Cheney recalls urging the president several times to pardon Libby because he felt he wasn't treated fairly in the investigation, and writes that Bush's decision was a "grave error."

In the book, Cheney also offers less than flattering assessments of his former colleagues in the Bush administration, including former secretary of state Colin Powell and the woman who replaced him in the position, Condoleezza Rice.

The book claims Powell was silent at cabinet meetings over his opposition to the Iraq invasion, an assertion the now-retired Powell denies.

During Tuesday's interview, Cheney said his goal for the memoir was that a "balanced account required me to put down what my opinion was."

He also noted the book contains "a lot of very positive stuff" on Powell's career in the military and his time as chairman of the joint chiefs of staff while Cheney was defence secretary.

Powell accused Cheney over the weekend of taking "cheap shots" at members of Bush's administration to publicize his memoir, and also disputed Cheney's assertion in the book that he was responsible for pushing Powell out of his role in 2004.