But he also pushed for a mission to Mars: "The best way to honour and remember all those who were part of the Apollo programme is to follow in our footsteps; to boldly go again on a new mission of exploration."
Mr Collins, who circled the Moon alone while Mr Armstrong and Mr Aldrin walked on it, said Mars was more interesting than the Moon.
"Sometimes I think I flew to the wrong place. Mars was always my favourite as a kid and it still is today."
He urged further exploration, saying: "I worry that the current emphasis on returning to the Moon will cause us to become ensnared in a technological briar patch needlessly delaying for decades the exploration of Mars - a much more worthwhile destination."
Other Nasa astronauts gave a news conference at Nasa headquarters in Washington DC on Monday.
Eugene Cernan, who was the last astronaut to step off the Moon, concurred with the Apollo 11 astronauts urging a new focus on Mars.
My glass has been half empty for three decades at least. Hopefully, we can turn that around because what we did then is do-able again
Eugene Cernan, former Nasa astronaut
"We need to go back to the Moon, we need to learn a little bit more about what we think we know already, we need to establish bases, put new telescopes there, get prepared to go to Mars. The ultimate goal, truly, is to go to Mars," he told journalists.
Mr Cernan said that when he came back from the Moon in 1972, he believed that Nasa would mount a return mission to the lunar surface by 1980 and a manned mission to Mars by the turn of the century.
"My glass has been half empty for three decades at least. Hopefully, we can turn that around because what we did then is do-able again," he said.
"I think the next major goal is not to spend three days, or three weeks or three months on the Moon, but to have you folks, or your kids, or your grand-kids sit here and talk to a group of guys who can tell you what it was like to go to Mars."
Buzz Aldrin said the Moon should not be used as a testing ground for Mars
But Mr Aldrin disagreed with the view that astronauts should test capabilities for a long-duration flight on the Moon before attempting a journey to Mars.
"Why go to the most difficult place to do that? Why not do it on the International Space Station," he said.
Mr Aldrin added: "One day, we are going to send some people to the surface of Mars. And if we think we're going to send them there for a year-and-a-half and then bring them back, and then send another group there for a year-and-a-half and bring them back, Washington will find another way to spend that money.
"That's unless we have declared our objective is an increasing, permanent space settlement."
The US space agency's currently stated aim is to return astronauts to the Moon by 2020. But that vision is under review, along with the space vehicles that would get them there.
Nasa is due to retire its space shuttles next year and replace them with the Orion spacecraft, an Apollo-like capsule that would launch on a new rocket called Ares 1.
Another rocket, Ares V, would have the capability to launch heavy payloads - service and cargo modules - that would be needed to service Moon missions.
What should Nasa tell its astronauts to do on Mars?'
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