Phosphate mining may go ahead following an approved environmental clearance, but a researcher says strong monitoring will be critical to protecting Namibia's marine environment.

Hundreds of people in Walvis Bay have petitioned the Ministry of Environment, Forestry and Tourism (MEFT) to reconsider the environmental approval for marine phosphate mining.

Namibia has approved environmental clearance for marine phosphate mining about 120 kilometres southwest of Walvis Bay.