LISBON - AN EARTHQUAKE may have played a role in the collapse of a cliff on to a packed beach in Portugal's Algarve region, which killed five people, the country's environment minister said on Saturday.

'Several factors could have contributed' to Friday's tragedy at the popular resort of Albufeira, 'and among the probable causes we are looking into is Tuesday's earthquake,' Mr Francisco Nunes Correia was quoted as saying by the Portuguese news agency Lusa.

The quake measuring 4.2 on the Richter scale shook southern Portugal but without causing casualties or damage.

Its epicentre was 110 kilometres south of the city of Faro and it was felt in several tourist resorts in the Algarve.

Mr Jose Alveirinho Dias, professor of geology at the university of the Algarve, and Orlando Boreges, president of the National Institute of Hydrology (INAG), also said the seismic vibrations could have helped cause the accident.

Portugal's meteorological institute however was more cautious saying it was not known how unstable the cliff had been at the time.

'The level of vibrations felt at the accident spot (during the earthquake) was of very week intensity,' Mr Fernando Carrilho, director of Meteo Portugal's seismology and geophysics department, told reporters.

The partial collapse of the cliff on the Maria Luisa beach, which attracts foreign tourists and celebrities, killed five people and injured three according to the latest toll issued by the Civil Protection authority. -- AFP