Exploding an asteroid to avert a possible collision with earth in 2036 could have dire results, according to a Queensland University of Technology academic.

Dr Stephen Hughes, from QUT's School of Physical and Chemical Sciences, said the classic Hollywood method of exploding an atomic bomb next to the asteroid could result in lots of mini-asteroids all still heading for the earth.

"It could create a shot-gun effect, sending showers of rocks hitting the earth," Dr Hughes said.

Dr Hughes was responding to reports from the US this week calling for the United Nations to develop a blueprint for a global response to an asteroid threat.

"The reality is that near-miss asteroids are very common - there are thousands of asteroids being detected in space," Dr Hughes said.

"Normally what happens is that as more information comes to light - by tracking the object with a telescope or even radar - it is discovered that the asteroid will not hit the earth after all."

Dr Hughes said another more effective method that has been suggested is to attach a rocket to the asteroid to nudge it out of its orbit slightly.

"Only a very small deflection is required to ensure that the asteroid will miss the earth."