(Reuters) -China Development Bank Financial Leasing said its aircraft leasing unit would order 50 Boeing 737 MAX 8 jets, in a boost to the planemaker that has been grappling with a slowdown in Chinese orders and a strike by factory workers.

Publicly disclosed Boeing plane purchases by Chinese customers had slowed significantly since Sino-U.S. trade relations deteriorated in 2018 and the manufacturer dealt with a lengthy return to service for the MAX in China after two deadly crashes.

The order for 50 MAX jets is the largest by a Chinese customer since China Southern Airlines ordered the same number of MAX planes in 2015, according to data from Boeing's website. Boeing declined to comment.

The planemaker's deliveries to China had been gradually recovering in recent months after a lengthy hiatus.

CDB Aviation Lease will take delivery of the planes between 2028 and 2031, its parent said in a statement, adding it would boost the proportion of next-generation aircraft in its fleet.

The deal comes less than a week after more than 30,000 Boeing factory workers went on strike seeking higher pay, which has resulted a halt to production of the planemaker's best-selling aircraft, the MAX, among other airplanes.

Boeing said on Wednesday that tens of thousands of workers will be placed on temporary suspension due to the strike.

The MAX order is the second major aircraft deal announced by China Development Bank Financial Leasing in the last week. The firm last week said it would purchase 80 Airbus A320neo planes, with deliveries expected to begin in 2030.