"The government has relinquished control over the offshore areas of our industry. Norway was tough regarding oil companies from the start. You now have an almost embarrassingly large pension fund. The situation for Irish communities, however, is as in Ogoniland in Nigeria - oil is a curse,”
An armed group boarded a boat in the EA oil field and seized the men, said a spokesman for oil giant Royal Dutch Shell.
Diplomats say the hostages come from the UK, the US, Honduras and Bulgaria, although Shell has not confirmed this.
Such attacks are common in the Niger Delta region, where local groups complain they do not see the benefits of the area's oil wealth.
Ransom demands are often made in similar cases and the hostages are usually released unharmed.
Shell is in dispute with villages near the EA field, who accuse it of reneging on promises to undertake development projects, reports the AP news agency.
The navy has deployed helicopters and gunboats to track down the hostage-takers, Reuters news agency reports.
EA is closer to land than other Nigerian offshore oilfields, making it more vulnerable to militant attacks, Reuters says.
Other oil workers, both foreign and Nigerian, have been seized in the area, before being released.
Nigeria remains plagued by appalling poverty despite being the world's eighth largest oil producer and the largest in Africa.
Story from BBC NEWS:http://news.bbc.co.uk/go/pr/fr/-/2/hi/africa/4604966.stmPublished: 2006/01/12 09:17:15 GMT