Boeing on Monday sweetened its contract offer and said it was its "best and final" proposal for its more than 30,000 machinists as their strike, which has halted most of the aerospace giant's aircraft production, entered its second week.

The new offer raised pay, reinstated annual bonuses and increased a bonus that would be given upon the contract's ratification, among other changes, Boeing said on its website.

The company's new offer would boost general wages by 30% over four years, up from a previously proposed 25%. It also doubled the ratification bonus to $6,000, reinstated an annual machinist bonus and raised the company's 401(k) match.

The labor union, the International Association of Machinists and Aerospace Workers, said Monday that it is reviewing the offer.

"Boeing executives have always known they could do better and this proposal shows the company can do better," Brian Bryant, the union's international president, said in a written statement.

Boeing said the offer is contingent upon ratification by Friday at 11:59 p.m. PT.

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