A former Canadian defence minister has claimed that aliens are real and has accused world leaders of keeping their presence on Earth, a secret.

Paul Hellyer, who was the North American country's defence minister from 1963 to 1967, is now urging world powers to release what he believes to be hidden data about UFOs, reports the Daily Mail.

The 91-year-old referenced a "New World Order" and the "cabal [secret political faction]" in his keynote speech at the University of Calgary on Saturday, 18 April as part of his Disclosure Canada tour, which calls for governments to open up their UFO files.

"Much of the media won't touch it," Hellyer told the crowd, according to CTV News. "So you just have to keep working away at it and we will get a critical mass and one day they will say, 'Mr. President or Mr. Prime Minister, we want the truth and we want it now because it affects our lives'," Hellyer said.

US government knows about imminent intergalactic war?

Hellyer first went public with his belief in aliens on Earth in 2005, becoming the first high ranking politician to do so. The same year he asked Canada to hold public hearings on extra terrestrials, as per the UFO Digest. In what can be termed as his most outlandish claim, Hellyer also accused the US government of planning an intergalactic war in 2005.

In 2014, Hellyer stated, during an interview on Russian TV, "We have a long history of UFOs and of course there has been a lot more activity in the last few decades since we invented the atomic bomb."

"They [aliens] are very concerned about that and that we might use it again, because it affects not just us but other people in the cosmos," he added.

'Aliens already living among us'

Hellyer also declared, during the interview, that aliens are walking among us. He claimed that the aliens have "been visiting our planet for thousands of years" and are unimpressed with how we live.

"We spend too much time fighting each other, we spend too much money on military expenditures and not enough on feeding the poor and looking after the homeless and sick," he said.

He told Russia Today's programme SophieCo there are 80 different species of extra-terrestrials some of whom "look just like us and they could walk down the street and you wouldn't know if you walked past one".

What aliens on Earth look like

Hellyer described several types of aliens including "Tall Whites" who are working with the US air force in Nevada.

"They're able to get away with that; they had a couple of their ladies dressed as nuns go into Las Vegas to shop and they weren't detected," he claimed.

Another group of aliens are called "Short Greys" who have very slim arms and legs and are about five feet high with large heads.

A third group are called "Nordic Blondes" and Hellyer said that if you meet one you would probably say, "I wonder if she's from Denmark or somewhere."