North Korea is preparing for a long-range ballistic missile test, according to a satellite company that has analysed images of the launch site.

DigitalGlobe, which provides commercial satellite imagery to the US government and foreign governments, on Monday released a new image it claimed showed increased activity at North Korea's Sohae (West Sea) satellite launch station.

This activity is consistent with launch preparations as witnessed prior to the failed April 13, 2012 launch of the Unha 3 (i.e., Universe or Galaxy 3) space launch vehicle (SLV) carrying the Kwangmyongsong 3 (i.e., Bright Lodestar 3), DigitalGlobe says in a statement.

"Given the observed level of activity noted of a new tent, trucks, people and numerous portable fuel/oxidizer tanks, should North Korea desire- it could possibly conduct its fifth satellite launch event during the next three weeks," the statement goes.

The Guardian has reminded that North Korea carried out nuclear tests in 2006 and 2009 and is under heavy UN sanctions for its atomic weapons program.