Islamic State (IS) militants have claimed responsibility for a suicide attack with an explosive-laden truck on an Iraqi police checkpoint at the entrance of the city of Hilla, south of Baghdad, killing at least 47 people.

Responsibility was claimed in a posting on the website of the Amaq news agency, which supports IS.

"A martyr's operation with a truck bomb hit the Babylon Ruins checkpoint at the entrance of the city of Hilla, killing and wounding dozens," the statement on the Amaq website said.

Officials said the vehicle was a truck packed with explosives and was detonated after being pulled over by checkpoint security as it tried to enter Hilla.

At least 70 people were wounded by the blast, security and medical officials said.

A provincial hospital official confirmed the number of casualties.

Many had suffered burn injuries.

Falah al-Radhi, head of the provincial security committee, said it was the largest bombing in the province to date.

"The checkpoint, the nearby police station were destroyed as well as some houses and dozens of cars," he added.

At least 45 people were killed by a similar attack in Hilla in early 2014, but IS has not had fixed positions south of Baghdad since security forces and allied militias began their fightback against the jihadists in late 2014.

Hilla is the capital of the province of Babylon, a predominantly Shiite region with some Sunni presence.

Brett McGurk, the US envoy to a coalition fighting IS, said on Saturday the militant group was losing the battle against forces arraigned against it from many sides in Iraq and Syria.

He said the focus would turn to stabilising cities seized back from them.

AFP/Reuters