Families of 12 passengers on Malaysia Airlines Flight 370 have sued the carrier and the Malaysian government.
The move comes ahead of a filing deadline next week on the second anniversary of the plane's disappearance.
The Boeing 777 carrying 239 people flew far off course for unknown reasons after leaving Kuala Lumpur for Beijing on March 8 2014.
An ongoing search of the southern Indian Ocean has found no trace of the plane, although a wing part from the aircraft washed ashore on Reunion Island last year.
A global aviation agreement sets a two-year deadline for lawsuits by next-of-kin over air accidents.
Lawyer Sangeet Kaur Deo, who is representing 10 families, said the lawsuits involve a passenger from Russia, one from China and the rest from Malaysia.
Apart from the airline, the lawsuits also named the government and the then heads of the civil aviation department and the navy as defendants.
Ms Sangeet said her clients were engaged in settlement negotiations with the airline earlier.
She said: "Everyone waited till the last minute to give time to the airline to settle but nothing reasonable was forthcoming. So they have no choice but to take legal action given the time limitation."
Lawyer Yeoh Cho Kheong, who is representing the families of two Ukrainian passengers, said his clients will continue negotiations with the airline despite the lawsuit.
The two men, aged 44 at the time, were partners in a furniture business. The families said they each earned 2 million US dollars (£1.4 million) annually and were on their way to Beijing for a business deal, according to Mr Yeoh.
"If an out-of-court settlement can be achieved, I believe my clients will accept it," he added.
All the lawsuits are seeking unspecified sums for negligence and breach of contract, the lawyers said.
Ms Sangeet said she expects to file two more lawsuits on Monday, the last day for filing.
An international aviation agreement allows each next-of-kin of passengers on board a plane up to 175,000 US dollars (£123,000) in compensation, but a plaintiff filing a lawsuit can seek more.
A Boeing 777 flaperon was found on an island in the western Indian Ocean in July and confirmed by the Malaysian and French governments to have come from the ill-fated plane.
Drift modelling has shown that currents could have carried debris from a suspected crash site in the southern Indian Ocean to Reunion Island.
An ongoing search in the southern Indian Ocean is expected to end by June or July.