China earthquake
Doctors attended to quake survivors with mild injuries at the Jishishan County People's Hospital. AFP

Chinese earthquake survivors recovered in hospital as rescue teams rushed to deliver supplies on Thursday, the third day since the country's deadliest quake in years killed 135 people.

The toll rose from the previous day's 134, state news agency Xinhua said, as rescuers continued to search for victims buried as the soil liquified in northwestern Qinghai Province.

Almost 1,000 were injured across Qinghai and neighbouring Gansu province after the strong, shallow tremor hit the region on Monday night.

At the Jishishan County People's Hospital in Gansu, near the epicentre of the quake, doctors attended to survivors with mild injuries on Thursday, administering intravenous drips and examining X-rays in buildings visibly damaged by the tremor.

"I really want to go home," one patient, a middle-aged woman waiting to receive surgery on her injured leg, told AFP.

"But my place has been destroyed, so I wonder where I can go," she said.

"People are still worried about the aftershocks, they can't sleep well because there is no safe place", a Jishishan county official told AFP.

The US Geological Survey said Monday night's magnitude-5.9 quake struck at 11:59 pm local time (1559 GMT) with an epicentre about 100 kilometres (60 miles) from Gansu's provincial capital, Lanzhou.

Dozens of smaller aftershocks followed and officials warned that tremors with a magnitude of more than 5.0 were possible in the next few days.

Rescuers from across the country appeared to have reached more survivors in rural Gansu overnight, with AFP reporters seeing that large numbers of government-issued blue tents had been put up in Jishishan to replace improvised shelters built by residents immediately after the quake.

In Qinghai province, 12 people remain missing after a "sand boil" disaster on Tuesday buried people alive and in Zhongchuan Township, according to Xinhua.