His release comes amid a spate of arrests of human rights activists in the country.
According to religious freedom Christian Solidarity Worldwide (CSW), Pastor Nguyen Cong Chinh was prisoner of conscience, and was only released on the basis that he leaves Vietnam.
CSW said Pastor Chinh, who is a passionate advocate for religious freedom and the rights of ethnic minorities and indigenous peoples, had been serving an 11-year sentence for 'undermining national'.
The charity claimed the pastor's health deteriorated to a potentially life-threatening level because of ongoing abuse during imprisonment. His wife, Tran Thi Hong, an activist with Vietnamese Women for Human Rights was also reportedly interrogated, harassed and beaten by the authorities on several occasions.
CSW's Chief Executive Mervyn Thomas welcomed the pastor's release but is appalled that he will have to be exiled.
He said: "We condemn the targeting by the authorities of both Pastor Chinh and Hong, in particular the harassment and physical abuse they have both endured simply for advocating for the rights of their fellow citizens."
Chinh's release comes amid a series of arrests of activists and religious freedom advocates in Vietnam.
Nguyen Bac Truyen, an activist was arrested on 30th July and charged with 'carrying out activities aimed at overthrowing the people's administration'.
He has been harassed and attacked numerous times in connection with his advocacy for human rights and religious freedom. Three other activists have been arrested on the same charge.
In a statement on 28th July, the Office of the UN High Commissioner for Human Rights (OHCHR) expressed concern over "the intensifying crackdown in Viet Nam against human rights defenders who have questioned or criticised the Government and its policies," stating that "human rights defenders should never be treated as criminals who are a threat to national security".