"We stand ready to give help to the Nigerians to deal with lawlessness that exists in this area and to achieve the levels of production that Nigeria is capable of, but because of the law and order problems has not been able to achieve," Brown told a news conference at the Group of Eight summit.

Brown said he would be meeting Nigerian President Umaru Yar'Adua in London next week.

Yar'Adua, also in Japan this week for a G8 gathering with African leaders, called for a global clampdown on the theft and smuggling of crude oil, an international trade which is fuelling unrest in the Niger Delta.

Nigeria is the world's eighth biggest oil exporter but the bombing of pipelines and kidnapping of oil workers in the delta's creeks have cut production by around a fifth since early 2006, helping to push world oil prices to record highs.

Yar'Adua has said his administration will take a two-pronged approach to the unrest, pledging development for communities whose land and water have been polluted by oil extraction but also saying he will not tolerate the presence of armed groups.

Nigeria has long been publicly opposed to the idea of foreign involvement in resolving the Niger Delta crisis, which it says is a purely domestic issue.