A company working on the redevelopment of Dun Laoghaire baths has begun a massive clean-up after a plastics spill at Dublin's Forty Foot.

SIAC has confirmed that fibres were washed into the sea while concrete was being poured at the site.

Dun Laoghaire-Rathdown County Council says it's crews have been assisting in the clean-up since yesterday afternoon - when plastic strips began washing up along Sandycove Beach.

The council says its keenly aware of the potential impact of the spill and it's demanded a full investigation.

The Mayor of Dun Laoghaire, Councillor Ossian Smyth says he's outraged and is demanding accountability.