The hold-up, in which the driver was also shot dead, happened in the Akpabuyo district near the capital of Cross River state, Calabar, at about 7 am (0600 GMT) today.
All five were workers with Australian mining and engineering giant Macmahon, which was contracted to cement major LafargeHolcim in the state, police commissioner Jimoh Ozi-Obeh told reporters.
"The police is currently working with the Nigerian Navy to ensure that the victims are released unharmed," he added.
The commissioner said no ransom demand had been received.
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One witness to the abduction, who asked not to be identified, said the kidnappers took the men to a waiting boat.
LafargeHolcim spokeswoman Viola Graham-Douglas said the company was informed of the incident by Macmahon, which was "working with the security agencies to resolve the situation".
Macmahon has an USD 18 million per year contract with the United Cement Company of Nigeria Ltd (UniCem) for quarrying operations at UniCem's cement manufacturing plant at Mfamosing, near Calabar.
Kidnapping for ransom has been a long-standing problem in southern Nigeria, particularly in the oil-producing delta region, where criminal gangs target wealthy Nigerians and expatriate workers.
Most are usually released after the payment of a ransom.