State news agency Xinhua says more than 1,800 people have also been injured.

The quake in Qiaojia county of Zhaotong prefecture has left residents searching for survivors beneath the rubble of toppled buildings and communications and power lines, as images shared on social media show.

The United States Geological Survey (USGS) measured the quake at a magnitude of 6.1, striking 11 kilometres north-west of the town of Wenping at a relatively shallow depth of 10 kilometres.

It struck at 4:30pm Sunday local time.

State media reported the earthquake at magnitude 6.5, citing the China Earthquake Networks Centre.

"Too many buildings were damaged and we are collecting data on deaths and injuries," Xinhua quoted a local official as saying.

Xinhua says electricity and communications services have also been affected, adding that homes and older structures have been particularly affected.

Around 12,000 houses have collapsed and 30,000 damaged, Xinhua said.

State television says firefighters have been rushed to the epicentre and civil affairs authorities are sending tents and beds for people left without shelter.

Television footage shows people running from their homes and gathering in the streets.

One person, who says they live in Ludian county, 23 kilometres from the epicentre, has posted an image of cracked walls and a pile of bricks strewn across the road on China's Twitter-like Weibo.

Another Ludian resident speaking on Xinhua says the scene resembles a "battlefield after bombardment".

"I have never felt [such] strong tremors before. What I can see are all in ruins."

Ludian has a population of almost 266,000 people.

Zhaotong City, the prefectural capital, lies about 300 kilometres from the provincial capital Kunming.

The region sits where the Eurasian and Indian plates meet and is prone to earthquakes.

In 1974, a magnitude 6.8 quake in the area killed more than 1,500 people, while in September 2012 80 people died when twin earthquakes struck the mountainous border area of Yunnan and Guizhou.