Libya's deputy Prime Minister Awadh al Barassi has resigned from his office, slamming the government as "dysfunctional" and unable to end a wave of violence.

Barassi announced his resignation late on Saturday at a news conference in the restive eastern city of Benghazi, amid growing public anger over widespread violence and a spate of political assassinations.

Barassi’s resignation came just days after Prime Minister Ali Zeidan said he was shelving plans to carry out a cabinet reshuffle to improve the government's response to the unrest.

Blasting a "dysfunctional government", Barassi said he was stepping down due to "a security breakdown and assassinations linked to the cabinet's policies", state-run Lana news agency reported.

He said the government had failed to win the people's trust and provide state agencies with the resources needed to achieve development goals.

Zeidan expressed "surprise" but said he accepted Barassi's resignation, Lana reported.

On Monday, Zeidan said he would restore the feared Internal Security Agency which helped keep the ousted dictatorship of Muammar Gaddafi in power for decades, to try to stem the violence.

He also said he would reshuffle his cabinet but, on Wednesday, he said he was shelving the plans and would instead form a "crisis committee".

Many Libyans blame political rivalries for the problems plaguing a country awash with militias and weaponry left over from the 2011 revolution.

Since Gaddafi's overthrow, the Libyan authorities have struggled to re-establish order and form a professional police and army.

There has been a spate of attacks, particularly in the east of the country, the birthplace of the uprising, in recent past.

The attacks, some of which have struck several Western targets have been blamed on hardline armed groups.