(In March 22 story, corrects size of Zain's stake in paragraph 4)

RABAT - Moroccan telecoms company Inwi is suing market leader Maroc Telecom IAM.CS for more than 5.7 billion dirhams ($620 million) over alleged unfair competition, an Inwi official and a lawyer for the firm said on Thursday.

The lawyer, Abdelatif Wahebi, said the suit had been filed because "Maroc Telecom holds 60 percent of the market and the law says companies should hold no more than 40 percent".

No one from Maroc Telecom was immediately available for comment.

Inwi is the third largest telecoms operator in Morocco. It is owned by a holding company controlled by the Moroccan royal family. Kuwait's Zain ZAIN.KW and Kuwaiti Investment Authority's Al Ajial Investments bought 15.5 percent each in a joint deal for 31 percent of the operator in 2009.

Maroc Telecom, the North African country's largest telecoms operator, is controlled by the United Arab Emirates' Etisalat Group.

According to the most recent figures from Moroccan telecoms regulator ANRT, dating to December 2017, Maroc Telecom held 42.1 percent of the mobile market against 23 percent for Inwi.

Maroc Telecom held 84 percent of the fixed line telephone market against 12.6 percent for Inwi, and nearly 48.9 percent of the internet market against Inwi's 23.5 percent share.

(Reporting by Zakia Abdennebi; Writing by Aidan Lewis. Editing by Jane Merriman and David Evans) ((mailto:Aidan.Lewis@tr.com; +216-29850352;))