Boeing has agreed to plead guilty to a criminal fraud conspiracy charge to resolve a US Department of Justice (DOJ) investigation linked to two 737 MAX fatal crashes, a government official told Reuters.

The plea, which requires a federal judge's approval, would brand the plane maker with a felony.

Boeing will also pay a criminal fine of $US243.6 million ($AU360.73 million), a DOJ official says.

Boeing declined to comment.

The charge relates to two 737 MAX crashes in Indonesia and Ethiopia which occurred over a five-month period in 2018 and 2019. 

The crashes killed 346 people in total and prompted the families of the victims to demand Boeing face prosecution.

Boeing became exposed to criminal prosecution in May this year, after the DOJ found the company violated a 2021 settlement involving the fatal crashes.

On June 30, the DOJ offered a plea agreement to Boeing and gave the company until the end of the week to take the deal or face trial on a charge of conspiring to defraud the Federal Aviation Administration (FAA) over a software feature key to the fatal crashes.

A guilty plea potentially threatens the company's ability to secure lucrative government contracts with the likes of the US Defense Department and NASA, although it could seek waivers. 

However, the deal spares Boeing a contentious trial that could have exposed many of the company's decisions leading up to the fatal MAX plane crashes to even greater public scrutiny.

It will also make it easier for the company, expected to hire a new CEO later this year, to move forward as it seeks approval for its planned acquisition of Spirit AeroSystems.

Boeing has also agreed to invest at least $US455 million over the next three years to strengthen its safety and compliance programs, the official said.

The DOJ will appoint a third-party monitor to oversee compliance. The monitor will have to publicly file annual reports with the court on the company's progress.

After being briefed last week on the DOJ's offer, a lawyer for some of the crash victims' families criticised it as a "sweetheart deal".

The families have vowed to oppose the deal in court.

Reuters