A mudslide has disrupted rescue operations at a coal mine collapse in China's Inner Mongolia region that has killed at least two people, injuring six and leaving more than 53 people missing, according to state media reports.

The collapse happened on Wednesday at an open-pit mine in the Alxa League operated by Xinjing Coal Mining Co.

After the collapse, President Xi Jinping ordered search and rescue efforts, state media reported.

But the landslide on Wednesday evening led to the suspension of the search and it had not resumed by 6am local time on Thursday, state media reported.

There were no reports of any casualties in the mudslide.

Coal is a major source of energy in China but its mines are among the world's deadliest, largely due to lax enforcement of safety standards, despite repeated government orders for improvements in safety over the years.

Inner Mongolia is a major coal-producing region. China's mines have been trying to boost output over the past year under a government call for greater supplies and stable prices.

Before the mudslide, four rescue teams of 109 people were searching for the trapped miners, state media reported.

Authorities also sent 238 firefighters, 41 fire trucks and six rescue dogs to join the rescue and more teams of about 200 people were expected to arrive on Thursday, state media said.

Premier Li Keqiang demanded a quick investigation into the cause of the collapse.

The accident was the top trending discussion on the Weibo social media platform on Thursday, with some users saying most of the missing were dump truck and excavator drivers.

The National Health Commission said on Wednesday evening six injured people had been rescued and it had sent 15 ambulances and 45 medical staff to help with the rescue.

Reuters