"Now we have no news, and everyone is understandably worried. The relatives say they will go to the (Malaysian) embassy to find the ambassador," said Wen Wancheng, whose son was aboard the missing flight.
"The Malaysian ambassador should be presenting himself here. But he's not," Mr Wen said, updating reporters after a regular meeting between Malaysia Airlines officials and family members at a hotel in Beijing.
"Relatives are very unsatisfied. So you hear them saying 'hunger strike'," added the 63-year-old from the eastern province of Shandong, speaking as the search entered its 11th day.
Two-thirds of the passengers on the flight, which had 239 people on board, were Chinese.
Outside the meeting room, a woman clutching a placard reading "Respect life. Give us back our families" told reporters that the relatives were going on hunger strike.
She declined to say how many were doing so, or give her name.
"Since they haven't given us the truth about those people's lives, all of us are protesting," the woman said furiously.
"All the relatives are facing mental breakdowns," she added.
Wen also said some of the relatives had stopped going to the meetings, given how long they had been waiting for information.
"It doesn't mean giving up," he added. "It's normal to return home. Like me, I have been out for a long time."
Beijing has been critical of Malaysia's sharing of information, with state media and China's huge army of netizens in expressing anger at the handling of the incident by Kuala Lumpur.