"Beaches in north and south Goa were covered with black tar balls," eyewitnesses said.
"Entire south Goa beaches are covered with black oil which has been washed ashore," a source said.
Swapnil Naik, Tourism Department Director, said they have sent teams to take stock of the situation. He said there was no cause for panic.
"There is nothing to be alarmed. Usually such tar balls surface on the beaches during monsoons," Naik said.
Collision of two merchant ships off the Mumbai coast on Aug 7 had caused a massive oil slick in the metropolis' shores and some surrounding area.