Striking Boeing workers are set to vote on a new offer from the aviation giant, which includes a 38% pay rise over the next four years.

The International Association of Machinists and Aerospace Workers (IAM) union, which represents more than 30,000 striking workers, has endorsed the offer and says it will hold a ballot of its members on Monday.

The walkout started on 13 September, leading to a dramatic slowdown in production and deepening a crisis at the firm.

The union had previously called for a 40% pay increase and workers have rejected two previous offers, including the last offer of a 35% rise.

As well as the proposed pay rise, the latest offer includes a $12,000 bonus (£9,304) for the workers if a deal is reached, up from $7,000.

“It is time for our members to lock in these gains and confidently declare victory,” an IAM social media post said.

“We believe asking members to stay on strike longer wouldn’t be right as we have achieved so much success.”

Boeing said the offer would see average annual pay rise to $119,309 over the next four years.

“We encourage all of our employees to learn more about the improved offer and vote on Monday, November 4,” Boeing said in a statement.

The new offer also includes changes to workers’ retirement plans.

Boeing shares rose 2.7% in extended trading in New York after the proposed deal was announced.

Boeing has been trying to end the strike and shore up its finances.

Last week, its commercial aircraft business reported operating losses of $4bn for the three months to the end of September.

The company also launched a share sale to raise more than $20bn earlier this week.

It came after warnings that a prolonged strike could lead to downgrades to Boeing’s credit rating, which would make it more expensive for it to borrow money.

The firm is also moving ahead with plans to lay off around 17,000 workers, with the first redundancy notices expected to be issued in mid-November.

The latest crisis at Boeing erupted in January with a dramatic mid-air blowout of a piece of one of its passenger planes.

Its space business also suffered a reputational hit after its Starliner vessel was forced to return to Earth without carrying astronauts.