DUBAI - Boeing's 737 MAX took centre stage at the Dubai Airshow on Tuesday as the U.S. planemaker prepared to announce orders for dozens of aircraft as it seeks to restore confidence in the jet amid a worldwide grounding, people familiar with the matter said.

Boeing was expected to announce the orders, which could be worth $5-6 billion, a day after securing the first firm order for the aircraft since the grounding from Turkey's SunExpress.

Global regulators banned commercial flights of Boeing's fastest-selling jet in March after two fatal accidents.

Boeing is in the process of modifying software and pilot training which will require regulatory approvals.

In other news, budget airline easyJet exercised the purchase rights to order 12 more Airbus A320neo aircraft, Airbus said on Tuesday.

Airbus is also prepared to unveil an order for 8 of its small A220 jets from Air Senegal, delegates said.

Also coinciding with the show, leasing giant GECAS was expected to confirm an order for 25 Airbus jets including 12 A330neo powered by engines from Rolls-Royce, a competitor to GECAS parent company General Electric.

However, there were no immediate signs that Dubai's Emirates was ready to finalise a provisional order for 40 Boeing 787 Dreamliners, part of a complex set of interlocking deals driving fleet changes at the world's largest international airline.

The fate of the order hinges on negotiations over the larger Boeing 777X for which Emirates is the largest customer. Emirates has indicted it wants to restructure the order following delays and sources say it could use the pending 787 deal as leverage.

(Reporting by Tim Hepher; editing by Shri Navaratnam and Jason Neely) ((asma.alsharif@thomsonreuters.com; +20225783290; Reuters Messaging: asma.alsharif.reuters.com@reuters.net))