DUBLIN - Aircraft leasing firm SMBC Aviation Capital has agreed to buy an additional 14 Boeing 737 MAX aircraft with a low-cost carrier configuration, with deliveries due to begin later this year, it said on Tuesday.

The company, a major Boeing customer, had previously disclosed firm orders for 89 MAX jets and a commitment to a fleet of 133.

But last year during the grounding of the MAX and at the height of the COVID-19 pandemic it deferred delivery of 68 of those jets by four years until 2025-2027 and indicated it had not ruled out cancellations.

"We are pleased to have concluded an agreement with Boeing for the purchase of 14 low-cost carrier configured 737 MAX aircraft which is an aircraft we are seeing increased customer demand for following its successful return to service," Chief Executive Peter Barrett said in a statement.

Aircraft leasing firms, which control over 40% of the global fleet, are among the largest MAX customers.

Industry sources told Reuters last week that Boeing had drawn up preliminary plans to boost 737 MAX output to as many as 42 jets a month in fall 2022 from single digits now as it prepared for a recovery from overlapping safety and COVID-19 crises.

Production was halted in 2019 after Boeing's fastest-selling model was grounded in the wake of fatal crashes. It resumed last May at a fraction of its original pace while Boeing navigated regulatory approvals and a fragile supply chain.

SMBC Aviation Capital is owned by a consortium including Japan's Sumitomo Corp and Sumitomo Mitsui Financial Group.

(Reporting by Conor Humphries, editing by Louise Heavens and David Evans) ((conor.humphries@thomsonreuters.com; +353 1 236 1915;))