China Eastern Airlines has formally begun the compensation process for the families of the 123 passengers and nine crew members who perished in the MU5735 plane crash, the airline said on Sunday.

The airline has organized a team to handle insurance claims and will communicate with families to develop compensation plans based on relevant laws and regulations, said Liu Xiaodong, head of the airline's publicity department.

More than 60 insurance companies involved in the accident have started emergency response plans.

"Compensation depends on negotiations between the airline and the families, while government departments like the Civil Aviation Administration of China will help to achieve a compensation agreement," said a lawyer.

A plane crash usually takes a long time to investigate, sometimes more than two years, so it is still difficult to draw a conclusion, said the lawyer.

The plane's manufacturer may also be liable for compensation.

Boeing extended its condolences for the loss of those on board the flight in a statement released on China's social media site Weibo on Saturday.

"We extend our deepest condolences for the loss of those on board China Eastern Airlines Flight MU5735. Our thoughts and prayers are with the passengers and crew, their families and all those affected by this accident," said the company.

"Boeing will continue to support our airline customers during this difficult time. In addition, a Boeing technical team is supporting the NTSB and the Civil Aviation Administration of China, who will lead the investigation," it added.

At present, the two black boxes from MU5735 have been found and will help find out the cause of the crash.