Nigeria's Senate is reportedly to ask a Shell unit to pay $1.5bn (£0.84bn) compensation to oilfield communities for environmental damage.
Shell says the resolution has to be backed by law
"The motion was overwhelming passed and the Senate Committee on Petroleum was asked to monitor compliance," Reuters quoted a Senate spokesman as saying.
Shell Petroleum Development Corp (SPDC), owned by Royal Dutch/Shell, said it was unaware of the ruling.
The resolution is said to follow a petition by members of the Ijaw tribe.
They are based in the southern Bayelsa state, where Shell and other multinational companies have operations.
SPDC operates through a joint venture in Nigeria, in which it owns 30% while state-run Nigerian National Petroleum Corp owns 55%.
SPDC is also one-tenth owned by France's Total, and Agip, a unit of Italy's ENI, owns 5%.
The petition was originally presented to the lower House of Representatives last year and reviewed by an independent legal advisory panel set up by the lower house.
According to the reports, the resolution says Shell is expected to pay $1bn now and the balance of $500 million in equal instalments over the next five years.
Shell in London said the Senate resolution had not been communicated to the company.
The company added: "SPDC strongly contested the claims made by the Ijaw Aborigines at a Public Hearing by a Committee of the Nigerian House of Representatives in May 2002.
"It is important to note that the Resolution that was eventually passed on the matter by the House of Representatives did not endorse the panel of jurists' recommendation to pay $1.5bn to the petitioners."