Australian company says workers freed after Nigeria kidnap

An Australian mining company says seven of its workers who were kidnapped in south-eastern Nigeria last week have been freed.

McMahon Holdings said three Australian workers were released along with a South African national, a New Zealander, and two Nigerians.

Five of the men are injured, two of them seriously, the company said.

The men were kidnapped when their convoy of cars was ambushed by gunmen near the city of Calabar on Wednesday.

Their Nigerian driver was killed in the attack.

Kidnap-for-ransom is a longstanding issue in southern Nigeria, where gangs target expatriate workers.

The head of McMahon Holdings, Sy van Dyk, said the men had been through a traumatic experience, Australian broadcaster ABC reported.

"We have mobilised medical and other support teams in Nigeria to provide immediate support," he said.

"I also thank the men's families for working so closely with the company during what has been an extremely difficult time for them as well."

It is still not clear how the company or the Nigerian authorities managed to secure their release.