As many as four Australians may be among a group of people kidnapped in a fatal ambush in south-eastern Nigeria.

Local authorities report that gunmen attacked their vehicle near the city of Calabar in the Cross River State around 5.30am local time.

The driver was shot dead in the attack.

Those kidnapped worked for Australian mining and engineering giant Macmahon, which was contracted to cement company Lafarge Africa.

A New Zealander, two Nigerians and a South African are also believed to have been taken.

Africa News reports that no one has claimed responsibility for the attack and abduction.

It also reports that kidnappings for ransom are a common occurrence in are, however it’s unusual for expatriates to be taken hostage.

A spokeswoman for Lafarge Africa said Australian contractor Macmahon was assisting authorities in the investigation.

Foreign minister Julie Bishop says the government was working to confirm details of the reported kidnapping.

“The Australian government is in close contact with the Nigerian government, which is taking the matter extremely seriously,” she said.

Macmahon has a seven-year contract for quarrying operations near Calabar in Nigeria, one of two operation Macmahon’s has running in the country.

According to a 2011 media release, it’s expected to generate revenue in the order of US$18 million per year.

An ASX/S&P 200 company, Macmahon has been running for 53 years and as of the end of the 2014 financial year, had a total of 2467 direct employees across all operations.

Macmahon Holdings has put its shares in a trading halt ahead as of 10am this morning off the back of the incident.

Here’s a map with the location of the area in which they were kidnapped from.

More to come.

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