A 2.5-kilometre wide asteroid is heading towards Earth this weekend.

An asteroid just 400 metres wide has the potential to devastate the planet.

Luckily, Nasa says Asteroid 86666 "poses no threat" of actually hitting earth.

The trajectory of 8666 in our solar system, with its position for October 10 illustrated. Photo: NASA.

Indeed, it won't get any closer than 25 million km - which counts for snug in space.

The rock is being monitored by Nasa's Jet Propulsion Lab's Near-Earth Object Observations program, which keeps track of the orbit of any objects within 30 million miles of Earth.

Asteroid 8666 was first spotted in March 2000 by the Catalina SKy Survey at the University of Arizona.

Many have speculated that the giant rock could hit earth.

The speculation reached such a fever pitch this year that Nasa ended up posting a blog in August dispelling any notion that the asteroid would collide with earth in late September.

"There is no scientific basis - not one shred of evidence - that an asteroid or any other celestial object will impact Earth on those dates," says Nasa's Paul Chodas.

The blog went on to clarify that "all known Potentially Hazardous Asteroids have less than a 0.01per cent chance of impacting Earth in the next 100 years."