A spate of car bombs in Shiite areas of Iraq, including two blasts minutes apart at a popular bird market, killed at least 29 people on Friday, the latest in a spike in violence amid a political crisis.

The attacks, which left nearly 70 others wounded, primarily targeted marketplaces that are often crowded on Fridays, the weekly holiday in Iraq, and took the death toll from a week of violence to more than 100.

Twin explosions that struck at a bird market in Baghdad's predominantly Shiite neighbourhood of Kadhimiyah, site of the shrine of a revered figure in Shiite Islam, killed at least 11 people and wounded 30 others, security and medical officials said.

The two car bombs were set off just after 9:00 am in the market, which is typically packed with people on a Friday.

And in the predominantly-Shiite Iraqi province of Babil, two car bombs in the town of Shomali, south of Baghdad, killed five people and wounded 11 others, according to security and medical officials.

The first explosion went off on the town's outskirts, while the second was detonated in a market.

Sunni militants, including Al-Qaeda's front group in Iraq, often target Shiite neighbourhoods with deadly attacks in a bid to push the country back to the sectarian bloodshed that blighted it from 2005 to 2008.

The violence is the latest in a spike in unrest in Iraq, which has been struck by waves of car bombs and suicide attacks in recent weeks amid a political crisis and weeks of rallies in Sunni-majority areas calling for the ouster of Shiite prime minister Nuri al-Maliki.

A total of 89 people have been killed in violence nationwide in the past week, and January was the deadliest month in Iraq since September according to an AFP tally.

Among the attacks since Saturday was a string of three suicide bombings in as many days.