The protester, Yasser Makki, died in hospital and six more people were wounded in demonstrations over poor government services and corruption, local health and security sources said.
Mourners carried Makki’s body near the site where he was wounded, chanting “Yasser’s blood will not be lost’’.
They damaged the gate of the provincial government headquarters but were dispersed by security forces using tear gas before they could enter the building. More protests would take place by Tuesday night.
The local head of Iraq’s Human Rights Commission, Mahdi al-Tamimi, called for an investigation into Makki’s death.
“We call on the Iraqi judiciary to open an immediate and urgent investigation into the killing of a demonstrator who was shot in the shoulder and subjected to electric shocks by security forces,” Tamimi said in a statement.
Hundreds of people had gathered near Basra’s provincial government building on earlier to press demands for better public services and an end to corruption.
Protesters threw petrol bombs and stones at security forces, who responded by firing shots into the air and tear gas, security sources said.
Protests have swept cities in the long-neglected south, Iraq’s Shi’ite Muslim heartland, over electricity outages during the hot Iraqi summer, a lack of jobs and proper government services, and entrenched graft.
Prime Minister Haider al-Abadi suspended the electricity minister in August and said that his government had begun punishing those responsible for poor services in Basra, Iraq’s second biggest city.
But public anger has swelled at a time when politicians are struggling to form a new government after an inconclusive parliamentary election in May.
Iraq’s top Shi’ite cleric Grand Ayatollah Ali al-Sistani has expressed support for the protests.
On Friday, hundreds of protesters clashed with security forces in Basra as they tried to break into the provincial government headquarters.