An oil spill that originated from Syria's largest refinery is growing and spreading across the Mediterranean Sea and could reach the island of Cyprus by Wednesday, Cypriot authorities have said.

Syrian officials said last week that a tank filled with 15,000 tons of fuel had been leaking since August 23, at a thermal power plant on the Syrian coastal city of Baniyas. They said they had been able to bring it under control.

Satellite imagery analysis by Orbital EOS now indicates that the oil spill was larger than originally thought, covering around 800 square kilometres (309 square miles) -- an area around the same size as New York City. The company told CNN on Tuesday evening that the oil slick was around 7 kilometers (4 miles) from the Cypriot coast.

The Cypriot Department of Fisheries and Marine research said that, based on a simulation of the oil spill's movements and meteorological data, the slick could reach the Apostlos Andreas Cape "in the next 24 hours." The department posted the statement at around 11 a.m. local time (4 a.m. ET) on Tuesday.

It also said it would be willing to assist in tackling the spill.

Apostlos Andreas Cape is in the Turkish-controlled north of the divided island and sits just over 130 kilometers (over 80 miles) west of Syria's Baniyas.

Photos circulating on social media for more than a week have shown the oil slick along with the coastal areas of Syria's Baniyas and Jableh, and locals have warned of a potential threat to marine life.

A resident in Baniyas, who spoke to CNN under condition of anonymity, much of the coast had been polluted.

"People did not need this, it is already hard to make a living here and this certainly affected the lives of many families and made them lose their income" the resident said.

"The government only sent teams with sponges and water hoses; they do not have the capacity to deal with this.... you cannot clean the sea with sponges," the resident added.

Turkey, which shares a border and coastline with Syria, has also been drawn in to contain the spill.

"We are taking the necessary measures by mobilizing our resources to stop any chances of the spill turning into an environmental disaster," Turkish Vice President Fuat Oktay told the state-run Anadolu news agency.

Baniyas refinery is the main source of Syrian fuel products and is essential to keeping the war-torn country powered.

This is the second major oil spill in the eastern Mediterranean this year. In February, an oil spill off the coast of Israel devastated the country's beaches and left tar deposits across the Lebanese coast.