Hundreds of firefighters are battling a forest fire in southern Catalonia amid fears it could turn into the worst blaze to hit the region for more than two decades.

Emergency services, including the Catalan police force, Red Cross and Spanish army, worked through the night to try and tame the wildfire, which has already burned through 5,500 hectares of land around the Tarragona region since Wednesday afternoon.

Imatges aèries del flanc dret de l'incendi. El video va ser fet en el darrer vol del vespre en l'helicòpter de #bomberscat. S'hi aprecien l'orografia abrupta del terreny i la dispersió de les flames, a causa del gran nombre de focus secundaris que ha fet #IFRiberadEbre pic.twitter.com/2kFpu0LHpI — Bombers (@bomberscat) 27 June 2019

High winds added to high temperatures in the Europe-wide heatwave, with highs of 40 degrees Celsius forecast in Catalonia over the coming days, and ensured the fire spread quickly, forcing the evacuation of 53 people and closure of several roads.

Particular concern surrounds the right flank of the fire, as the steep landscape prevents easy access, and a total of 20,000 hectares are considered at risk.

President Quim Torra is monitoring the operation at the command center in Vinebre, close to where the fire started, alongside interior minister Miquel Buch.

"If we can’t control the west flank, the fire could burn 20,000 hectares," said Buch.

Buch defended the involvement of the Spanish government as standard procedure for fires near the border between Catalonia and the rest of Spain. He added that had the fire been on the border with France, the French government would have assisted.