Hazim Tawfiq al-Ainachi was assassinated at a checkpoint in
the southern Iraqi city on Tuesday, he said.
"At the checkpoint, there were some people wearing police uniforms who asked the driver to stop. Then they opened fire," the spokesman said, adding that another man in the car was wounded.
Al-Ainachi's son, Isam, said: "My father was killed as he was leaving home at about 8am (0400 GMT) when unknown armed men fired at him from near a checkpoint that is 100m from our place."
The attack occurred in the Jubaila neighbourhood in the centre of Basra, which is 550km south of Baghdad and the second biggest city in the country.
Al-Ainachi was a coordinator for the provincial council and a former deputy governor in the city.
A series of attacks across Iraq
have targeted officials
The killing of al-Ainachi continues a series of attacks against figures in the new administration since power was handed over by the US-led occupation to Iyad Allawi's government on 28 June.
On Monday a senior defence ministry official was shot dead in Baghdad, while a week ago the governor of the northern city of Mosul, Usama Kachmula, was killed.
Though the intensity of violence in Basra has been less than in other parts of Iraq, fighting has occurred intermittently in this city, near Iraq's southern border with Kuwait.
In May, US-led occupation forces cracked down on the army of Shia leader Muqtada al-Sadr. Hundreds of al-Sadr's Mahdi Army fighters fought running battles with British troops over several days.
Also in May, oil exports from Basra's vital terminal were stopped following an attack on a pipeline, two weeks after US-led forces foiled boat attacks on tankers at the terminal.