Boeing said Tuesday it will give its machinists union more time to consider the company's latest labor contract proposal to end a strike that has shuttered two Seattle-area factories.

"We've reached out to the union to give them more time and offer logistical support once they decide to vote," Boeing said, amending a prior statement that set a Friday deadline for workers to accept the deal.

About 33,000 members of the International Association of Machinists and Aerospace Workers (IAM) in the Pacific Northwest region walked off the job on September 13 after overwhelmingly voting down an earlier offer, effectively shutting down assembly plants for the 737 MAX and 777.

On Monday, Boeing announced that it would lift wages for striking workers by 30 percent and reinstate an annual bonus, in concessions after workers walked off the job.

Boeing said the proposal is its "best and final offer."

The IAM slammed Boeing's offer, criticizing the company for releasing it publicly without giving union leadership time to comment, and for not giving the union enough time to organize a vote.

"The survey results from yesterday were overwhelmingly clear, almost as loud as the first offer: members are not interested in the company's latest offer that was sent through the media," union negotiators said in a message Tuesday.

"A 30% General Wage Increase (GWI) is progress, but it does not erase the fact that, over the past decade, our members have received only an 8% wage increase," they said, adding that 8 percent was not sufficient during a period of high inflation and rising costs of living.

The IAM negotiators said they were "ready to schedule mediated or direct talks with Boeing," and any resolution would then be presented to and voted on by union members.