Human rights groups have condemned the Algerian police for violently dispersing a sit-in organised by resident doctors in Algiers, who have been protesting for weeks over poor working conditions.

Images posted on social media show Algerian medical residents, who are still in training but serve as general practitioners in hospitals, with bloodied faces being helped away from the protest at CHU Mustapha Bacha, a university hospital in the capital, on Wednesday.

"We denounce the repression of the protest," said Amnesty International's Algeria branch, in a brief statement.

"The right to free expression and peaceful protest is guaranteed by the Algerian constitution."

Local media said several residents were injured in the violence, while videos shared on Facebook showed police, dressed in riot gear and shields, striking the protesters with batons.

The Casbah Tribune reported that one injured resident remains in hospital with a subdural hematoma, bleeding in the brain often caused by severe head injuries.

Eight residents were also arrested, but they have all been released, the news website said.

Organised by the Autonomous Medical Residents Collective (CAMRA, according to its French acronym), the sit-in drew dozens of medical staff from across Algeria, who chanted slogans outside the hospital.

The residents are angered by the state's requirement they fulfill civil service for a period of two years, which often means they are separated from their families.

The residents also want an increase in salaries and for general work conditions to improve.

They say the situation is especially difficult when they are deployed to work in more remote areas of Algeria, where they say they lack adequate housing, transportation and supplies with which to perform their medical duties.

CAMRA decried the "illegal and unacceptable excesses" of the police in its response to the sit-in.

In a statement, the group said the residents would suspend the minimum services they had guaranteed to provide despite their strike action, including emergency medical care, until all the detained residents were released.

The sit-in "traumatised the people that were present, especially since it took place inside a sacred space like a hospital", CAMRA said.

A committee for resident doctors in Oran, a city in northwestern Algeria, said it would organise another sit-in next week.

The national union of medical instructors and researchers at university hospitals and the national union of public health practioners also condemned the police violence and said they supported the residents.