Shell Pernis refinery to undergo planned maintenance until early May

(Adds details)

LONDON, March 3 (Reuters) - Shell (LSE: RDSB.L - news) 's 400,000 barrel per day Pernis refinery in the Netherlands, one of Europe's largest, has begun planned maintenance that will close large parts of the plant until early May, Shell's Dutch language website said.

The work, will involve one million man-hours of work by Shell employees and contractors, including an extra 2,000 staff a translation of the notice dated March 1 said.

A source said a crude distillation unit and a hydro cracker unit were down for maintenance. Reuters data shows there are two crude distillation units amounting to 200,000 bpd each. (Reporting by Himanshu Ojha, editing by David Evans)