CAIRO (Reuters) - Egyptian President Mohamed Mursi will call a parliamentary election starting in April, a presidential source told Reuters on Thursday, saying the vote would be held in three or four stages.

Earlier in the day the Shura Council, the upper house of parliament, adopted an electoral law as amended by the Constitutional Court, clearing the way for Mursi to set a date for the lower house election.

"The president will issue a decree soon, it could be tonight, calling for elections to start in April," the source told Reuters.

The vote would be held in phases in different regions because of a shortage of poll supervisors. The last lower house election, which was won by Islamists, lasted from late November 2011 until January the following year.

Mursi had been expected to ratify the electoral law by February 25. The lower house was dissolved last year after the court ruled the original law used to elect it was unfair.

(Reporting by Yasmine Saleh and Marwa Awad; Writing by Marwa Awad; Editing by David Stamp and Mark Heinrich)