Portugal's monthly unemployment rate slipped to 5.5% in May from 5.7% in April and from 6.2% registered a year ago, the National Statistics Institute (INE) said in its flash estimate on Wednesday.

The labour underutilisation rate stood at 9.4%, below the 9.7% posted in the previous month.

The youth unemployment rate encompassing 16- to 24-year-olds rose to 19.7% in May from 17.9% in April and was above the 19.5% registered a year ago, the INE said.