Two Christian activists have been deliberately targeted by Vietnamese police, according to human rights groups, with officers allegedly attacking one of them twice in less than a fortnight.

Tran Minh Nhat and Chu Manh Son have both suffered recent assaults which have been described as "part of a daily cycle of the systematic and pervasive rights abuse occurring across Vietnam" by Phil Robertson, deputy director of Human Rights Watch's Asia division.

Nhat was attacked on 17 November when he went for a medical check-up for the injuries he suffered from a similar attack just nine days earlier, Vu Quoc Ngu from local rights group Defend the Defenders told ucanews.com.

Undercover security officers assaulted Nhat as he travelled to the clinic near his home in Lam Dong province in the Central Highlands of Vietnam.

On 8 November Nhat and Son were assaulted after being stopped by police in the Central Highlands. They were then held for twelve hours, in which time both men were beaten and the communist party officials "tried to force [Nhat] to write a letter admitting to his wrongdoings," according to another rights group, Front Line Defenders.

"The police's blatant physical attacks and ongoing intimidation of these two dissidents show the Vietnam government's complete disregard for human rights or the rule of law," Robertson said.

"All across Vietnam, dissidents are being targeted this way – the only difference is whether the incidents become public or are hushed up."

Nhat and Son have both served lengthy prison sentences for political crimes; Nhat was released in August from a four year prison sentence and Son was released in 2014 after serving thirty months. They both claim to have been victims of police harassment since their release.

A journalist for Catholic organisation Vietnam Redemptorist News, Nhat was convicted with a number of his colleagues for conspiring to overthrow the government.

Son was convicted of using propaganda against the state.

Front Line Defenders told ucanews.com that there is little doubt that the two Christian activists "were specifically targeted on account of their peaceful work in defence of human rights."