Nguyen Tuong Thuy, 70, had his residence in Hanoi's Thanh Xuan District raided by the police as warranted by the HCMC People's Procuracy. Several documents and other evidence was found at the scene, said authorities.

Thuy's arrest is the latest development in a criminal case that saw 54-year-old Pham Chi Dung, a former member of HCMC's Party unit, arrested in November last year for 'dangerous' actions against the Vietnamese government.

Those found guilty of making, storing and spreading materials that opposes the Vietnamese state can be jailed for up to 20 years.