The cabinet on June 2 approved the special budget of 610 billion Taiwan dollars (18.2 billion US) for the purchase of advanced weaponry amid rising tensions with rival China. It is pending final approval by parliament.

Some critics say Taiwan cannot afford the expense while others say the new weaponry will not be delivered in time to help Taiwan fend off any Chinese attacks in coming years.

"An arms race between Taiwan and China would result in a disaster for the island as the military spending is a bottomless hole," Lin Shen-jing, director of Democracy Action Alliance, the rally's main organizer, said Monday.

"Besides, the hefty military spending will force the government to cut social welfare and education budgets which will also threaten the island's stability," he added.

The special defense budget calls for the procurement of eight submarines, a modified version of the Patriot anti-missile system and a fleet of anti-submarine aircraft over a 15-year period beginning in 2005.

Eleven academics from Taiwan's top leading research institution the Academia Sinica Monday also threw their weight behind the protest.

"Raising debts to purchase advanced weaponry without evaluating the effects would sacrifice the public's interests," they said in a joint statement.

"It will only lead Taiwan to an arms race by prompting China to expand its military equipment."

Lin said more than 60 retired generals have endorsed a petition against the special budget, with six of them intending to join the rally in the capital Taipei.

"I won't be surprised if more than 10,000 people show up to protest as the response is quite strong," he added.

China regards Taiwan as a renegade province and has repeatedly threatened to invade should the island declare formal independence.

The two sides split in 1949 after a civil war.