Tombs almost 1,000 years old in western China -- known as the "pyramids of the east" -- are in danger of collapse due to natural erosion and man-made damage, Chinese state television said on Wednesday.

One of the Western Xia Tomb that is in danger of collapse in Northwest China's Ninxia. [Xinhua]

The Western Xia Tombs, in the poor, remote region of Ningxia, house the remains of kings of an empire that once stretched to the borders of Tibet and developed its own complex written script based, like Chinese, on pictographs.

But years of wind, rain and neglect of the state-protected site has left holes up to two metres (yards) deep in the structures, which resemble miniature versions of Egypt's pyramids, the report said.

"The tombs are in imminent danger of collapse and urgently need to be saved," it said, adding that a 10-metre-long wall had already crumbled.

The tombs, spread out on a plain near an air force base outside the regional capital, are less preserved and protected than more famous sites, such as the Forbidden City in Beijing.

Many of their treasures were looted years if not centuries ago. All that is left now are a few artefacts in a dingy museum and the dusty remains of the tombs themselves.