Activists blame Shell for frequent oil leaks in the Niger Delta.
Leading human rights charity Amnesty International has joined calls for Nigeria’s government to stop Shell from selling its onshore oil business in the country.
The oil and gas firm’s proposed sale should be blocked unless human rights in the Niger Delta region are protected, Amnesty said.
The charity argued that a trade by Shell would risk worsening human rights abuses if the pollution caused by the company is not addressed.
It says Shell must provide sufficient funds to clean up the environmental damage it has caused and that local communities should be consulted on the sale, which is worth more than $2.4bn (£2bn).
Activists blame Shell for frequent oil leaks in the Niger Delta, which among other problems, have led to the contamination of groundwater sources.
Nigeria’s government has not commented on concerns about the sale.
Shell has previously promised that the new owners would deal with the damages.