CIVIC chiefs have urged people using Hampshire beaches to “exercise caution” after foam and discoloured water were sighted off parts of the south coast.

New Forest District Council has issued the warning after a “frothy scum” was seen in the water off parts of Hampshire and Dorset. Bournemouth Borough Council said the harmless marine algae was "non toxic" but New Forest council bosses urged people to exercise caution.

But authorities have received reports from beachgoers worried about what appeared to be pollution.

One woman who visited Milford on Sea yesterday is reported to have said: “The sea is very brown and slimy, with brown gloopy particles.” The algae bloom is said to be the biggest seen in the area for several years.

New Forest District Council said a deposit of oil was not suspected but advised coastal users to exercise caution until the cause and extent of the problem, was known.

The Environment Agency said the "brown frothy scum" seen in Dorset had been identified as Phaeocystis, a non-toxic algae which could be whipped by the wind into a brown foam.

A spokesman said: "Once onshore it breaks down into a brown slime which can smell similar to sewage."