An "unusually large" asteroid will hurtle past Earth but will not collide with the planet on Friday, astronomers said.

The asteroid, which is 10 times the size of an Olympic swimming pool, is one of 9,000 "near-Earth objects" recorded by Nasa, The Telegraph reported.

It will not be visible to the naked eye but stargazers can watch a live broadcast and catch a glimpse of it passing by Earth online.

Named LZ1, the asteroid is 500m (1,650ft) wide and is likely to get only within 14 times the moon's distance from Earth.

It was identified days ago by Scottish-Australian astronomer Rob McNaught at the Research School of Astronomy and Astrophysics of the Australian National University.

"Once in awhile one will come out of nowhere like this one, which is actually pretty big," said Patrick Paolucci, president of the skywatchers' site Slooh.