Kidnap Aussies are all well

THE employer of three Australians and a New Zealander kidnapped in Nigeria will not disclose whether it paid a ransom for their release.

Macmahon Holdings is based in Perth and said on Sunday night that seven of its workers had been released after they were grabbed last Wednesday.

A company spokesman said the mining firm was unable to make a comment about the paying of a ransom.

Macmahon chief executive officer Sy van Dyk said in a statement the men were courageous.

"Our men have been through a traumatic experience," he said.

Foreign Minister Julie Bishop said on Monday she believed the Australians were unharmed.

Ms Bishop also said the Federal Government did not pay to free the victims.

"The company will have to answer for itself, but the Australian government certainly does not (pay ransoms)," the MP told 2GB Radio.

"I believe that they are all well.

"They are undergoing health checks.

"It's obviously been a very traumatic time for them."

The men were grabbed and their Nigerian driver was killed in an attack on their convoy in Calabar on June 23.