Police in South Africa on Monday launched a manhunt after gunmen opened fire on a birthday party in the southern port city of Gqeberha, killing eight.

Three people were wounded in the shooting, which occurred on Sunday evening in a township of the city, previously known as Port Elizabeth.

The birthday celebrant and house owner was among those killed, police said.

"There was a birthday celebration at the house, and the next minute people from outside came in and started shooting randomly," police spokeswoman Priscilla Naidu told AFP.

The motive of the attack was unknown, and the victims were yet to be named.

Dozens of onlookers gathered outside the brown low-cost government-funded unit on Monday morning.

A barbecue grill, trays and empty packets of charcoal were lined against an outside wall, in a stark reminder of the celebratory mood that had filled the house the day before.

Mandla Booi, 55, a neighbour of the deceased, said he had made a lucky escape, as he had left the party just minutes before the shooting started.

"I passed through here yesterday and saw people enjoying themselves," he told AFP, adding he spotted a friend who invited him to join the party.

He "didn't stay long," he said. "It was less than 20 minutes (later) when I heard there was a shooting".

'Cold-blooded attack'

Shootings are common in South Africa, which has one of the world's highest murder rates, fuelled by gang violence and alcohol.

Many people have licensed fire arms for personal protection, yet there are many more illegal guns in circulation.

In November, six people were killed in a shooting at a house in Gqeberha's New Brighton township that police at the time said was a suspected drug den.

And nearly two dozen people were shot dead in a string of shootings at separate bars in working class suburbs of Johannesburg and in the eastern city of Pietermaritzburg.

The country, often described as one of the most dangerous in the world outside a war zone, has experienced a surge in violent crime over the past year.

Between July and September, it recorded more than 7,000 killings.

Authorities have been accused of failing to ensure safety and secure justice for the victims.

Nomthetheleli Mene, the provincial police chief for the Eastern Cape province, condemned the latest killings as "a blatant disregard for human life."

"We will not rest until we find out what happened and who was responsible for these callous and cold-blooded attack," she said.

Police Minister Bheki Cele and national police commissioner Fannie Masemola visited the scene on Monday.

He promised detectives would ascertain what had happen, acknowledging people were "angry" and wanted answers.

"We need to do and act faster quickly and decisively," he said.