An asteroid the size of a football field is about to make a close pass by Earth but is not expected to hit or cause any damage, NASA says.

Coined 2014 DX110, the asteroid will be part of a rare class of objects that comes nearer than the moon, and will shave by at about 2100 GMT (8am AEDT), the space agency said on Wednesday.

“As happens about 20 times a year with current detection capabilities, a known asteroid will safely pass Earth Wednesday closer than the distance from Earth to the moon,” NASA said on its website.

Its closest approach to Earth will be at about 350,000km, a bit closer than the average lunar distance of 385,000km.

The asteroid is believed to be about 30 metres across.

NASA discovered it as part of its asteroid tracking efforts, called the Near-Earth Object Observations Program.