South Korea has postponed a key satellite launch until the last week of November because of delays in the arrival of rocket parts from Russia, a senior official said Wednesday.

"We plan to inform international agencies of a new launch period of between November 23 and 30," the science ministry's Research and Development Policy Director Yang Sung-Kwang told journalists.

After two failures in 2009 and 2010, the planned rocket launch is considered crucial for South Korea's efforts to join an elite club of nations -- including Asian powers China, Japan and India -- capable of putting a satellite in orbit.

The launch was originally scheduled for October 26 but it was cancelled at the last minute after engineers detected a broken rubber seal in a connector between the launch pad and the rocket's first stage.

The 140-tonne Korea Space Launch Vehicle-1 (KSLV-1) has a first stage manufactured by Russia and a solid-fuel second stage built in South Korea.

The damaged seal was sent back to its Russian manufacturer for inspection and a new launch window was set between November 9-24, but delays in Russia shipping a replacement resulted in a second postponement.

Launch dates are provided in advance to international agencies to minimise risks to shipping and aircraft in the area.

In 2009 a South Korean rocket achieved orbit but faulty release mechanisms on the second stage prevented proper deployment of the satellite.

A 2010 effort saw the rocket explode two minutes into its flight, with both Russia and South Korea blaming each other.

South Korea is a late entrant into the world of space technology and is eager to get its commercial launch programme up and running.