(Reuters) - Portugal's monthly unemployment rate slipped to 6.5% in March from a revised reading of 6.6% in February, the National Statistics Institute (INE) said in its flash estimate on Thursday.

The labour underutilisation rate remained unchanged at 11.4% from the previous month.

The youth unemployment rate (16-24 years old) decreased to 22.3% in March, from a revised 22.4% in the previous month, but rose from 19.5% a year ago, the INE said.

(Reporting by Maria Luiza Amaral)