Demonstrators irate at the authorities in Iraqi Kurdistan took to the streets for a fifth day Friday, demanding the release of more than 200 protesters detained over violent rallies that have roiled the region.

Furious locals have torched the offices of the autonomous region's main political parties in a string of towns since Monday as ire boiled over at the calamitous fallout from an independence referendum.

September's overwhelming vote in favour of breaking away drew stinging reprisals from the central government that have battered Iraqi Kurdistan's already flagging economy and fired anger over official graft.

"Down with the government of the corrupt, no to corruption!" protesters in the town of Shamshamal, some 70 kilometres (45 miles) south of the region's second city Sulaimaniyah, chanted.

Protesters gathered in the town of Rania to demand that the "killers have to be brought to justice" after five demonstrators were shot dead there by security forces on Tuesday.

In Sulaimaniyah itself, police shot in the air and fired tear gas to disperse dozens of protesters calling for the release of those detained over the rallies.

Some 200 people have been arrested in the city alone since the protests began, while dozens have been held in other towns, activists from the Goran political party said.

The eruption of anger at the political elite in Kurdistan has caused turmoil for the authorities, with Goran and the Kurdistan Islamic Group party withdrawing from the regional government.

In the wake of September's independence referendum rejected by the central authorities, Baghdad seized back disputed oil-rich regions from the Kurds in a move that gutted their finances.

Veteran Kurdish leader Massud Barzani, who pressed ahead with the vote despite international opposition, announced he was standing down in October.

Prime minister Nechirvan Barzani, his nephew, has promised to hold postponed elections in the region in the coming months.