A large asteroid half a kilometre in diameter will “narrowly” pass Earth next week, with a second close encounter expected in 2027.

According to space agency NASA, asteroid ‘2004 BL86’ will pass 1.2 million kilometres from Earth, or around three times the distance to the moon, on January 26.

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The next asteroid expected to pass so close to the Earth is AN10, which is due to fly by in 2027.

2004 BL86’s safe flyby on Jan 26 is closest by any known #asteroid this large till 2027 http://t.co/z1ZoGXW0T2 pic.twitter.com/LYZhInSjY9

— Asteroid Watch (@AsteroidWatch) January 14, 2015

While the asteroid will safely pass Earth on Australia Day, NASA’s Near Earth Object Program office manager Don Yeomans said the fly-by still counts as a narrow encounter.

“While it poses no threat to Earth for the foreseeable future, it’s a relatively close approach by a relatively large asteroid, so it provides us a unique opportunity to observe and learn more,” Mr Yeomans said.

According to NASA, 2004 BL86 will be observable for amateur astronomers with telescopes and strong binoculars.

The Near Earth Object Program, also dubbed “Spaceguard”, tracks asteroids and identifies their approaches to determine if they are hazardous to Earth.