China claims self-ruled Taiwan as its territory and has ramped up military and political pressure on the island in recent years.

The two sides have been spying on each other for decades, but analysts say the threat to Taiwan is greater given that China has threatened to use force to bring Taipei under its control.

Nine of the defendants -- former and active military personnel -- were accused of "filming videos pledging allegiance to the CCP" (China's Communist Party) and "collecting and handing over classified military information" in exchange for money, the Ciaotou District Prosecutors Office said in a statement.

They were all serving in the army, navy, air force and coast guard when a "hostile foreign group" -- described to AFP as affiliated with the CCP -- approached them on social media and allegedly bribed them.

Prosecutors said the bribes -- paid in bank transfers and cryptocurrency -- ranged between NT$72,000 ($2,000) and NT$1.7 million ($53,500).

One civilian defendant was accused of offering the "hostile foreign group" use of his bank account to bribe army personnel in return for monthly payments.

It will be Taiwan's first national security case to be tried by citizen judges, following a law passed three years ago to bring the public into judicial decision-making.

By providing classified information to "hostile foreign forces", the former and current military personnel "seriously jeopardised national security," prosecutors said.

Prosecutors are seeking heavier-than-usual sentences as a "warning and deterrent" in the face of "increasingly serious" infiltration by foreign forces.

Espionage convictions in Taiwan can lead to sentences of 10 years or more.

The number of people prosecuted for spying for Beijing has risen sharply in recent years, with retired and serving members of Taiwan's military the main targets of Chinese infiltration efforts, official figures show.