Air safety has been a key concern for those tackling the Y2K computer bug.

Two test flights will leave Seoul at 2300 local time on Thursday and head for Beijing said the South Korean Ministry of Construction and Transportation, reported in the Korean Herald newspaper.

Another flight will head in the opposite direction.

Flying start

The official said that South Korea would send a government-owned aircraft for navigation safety analysis and a B737 passenger jet of Asiana Airlines. China will use a B737 jet from Air China.

At the start of the year China gave the heads of its airlines a strong incentive to solve any possible Y2K problems by ordering them to be in the air on 1 January 2000.

Jane Garvey, head of the US Federal Aviation Administration, had already pledged to fly across America on New Year's eve to demonstrate the safety of US systems.

In July, a British Airways flight from London to the South of France simulated New Year's Eve 1999. The jet's clocks were set to just before midnight and it continued the journey with no problem.

Pirate problem

However, China has a particular problem in that up to 90% of its software is estimated to be pirated, making it difficult to contact the original manufacturer for help.

In addition, much of the country's hardware and software has come from a wide range of countries and companies making the eradication of the Y2K problem complex.