MADRID (Reuters) - Spain's government continues to study a potential request for European Central Bank intervention in the debt markets, Economy Minister Luis De Guindos said on Monday.

"It is an instrument that the Spanish government is considering and we will take the decision that is best for Spain," he said in a radio interview.

De Guindos also said that he saw some signs of optimism in the Spanish economy but that uncertainties about the political situation in Italy, where Prime Minister Mario Monti has said he will resign, has a contagion effect on Spain.

(Reporting by Jesus Aguado, Writing by Clare Kane, Editing by Tracy Rucinski)