(Reuters) - Israel's aviation regulator has ordered airlines with Boeing Co (NYSE: BA) 737 jets converted to freighters by Israel Aerospace Industries (IAI) to comply with loading restrictions and use additional straps when needed before they can resume flying.

Its directive, published as an emergency airworthiness directive on the European Union Aviation Safety Agency website on Thursday, relates to 47 cargo planes that were grounded this week after IAI found an "apparent irregularity" in the production process of a rigid barrier that separates freight from the cockpit.

Australia's Qantas Airways Ltd operates four of the planes, while India's SpiceJet Ltd flies three. The other operators have not been identified publicly.

(Reporting by Jamie Freed; Editing by Muralikumar Anantharaman)