HELSINKI, Dec 20 (Reuters) - Finnish oil refiner and biofuels producer Neste expects to invest some 2.5 billion euros ($2.74 billion) to convert its Porvoo crude oil refinery to a biofuels production facility, the company said on Wednesday.

"The long term transformation of the Porvoo refinery is a key element in our renewables growth strategy," Chief Executive Matti Lehmus said in a statement.

Neste said it aims to complete the conversion by the mid 2030s. Estimated long-term capacity potential would be 3 million tons of renewable and circular products, it added.

The refiner and biofuels producer has grown rapidly in recent years having invested early in renewable fuels it makes from waste and residue, as industries and transport operators seek greener alternatives for fuels to cut their emissions.

($1 = 0.9129 euros) (Reporting by Anne Kauranen and Essi Lehto, editing by Louise Rasmussen)