The number of cancer cases in China is rising "ferociously", the World Health Organisation (WHO) warns.

According to the United Nations agency, around 2.2 million men and women across China die from cancer each year.

Lung cancer is now the most common cancer diagnosed in Chinese men, and the leading cause among cancer deaths in the country.

In a statement released on World Cancer Day, the WHO said many of the deaths could be prevented.

"The growth of cancer in China is ferocious," WHO China representative Dr Bernhard Schwartlander said.

"Improving cancer prevention in China – for example, by reducing very high smoking rates especially among Chinese men – would save many millions of lives every year.

"The single best thing you can do for your health is to stop smoking right now."

Smoking is still allowed in many enclosed public spaces, despite attempts by the Chinese government to impose a nationwide ban.

The WHO said air pollution was also a contributing risk factor for cancer, particularly in urban areas.

For Chinese women, breast cancer is the most commonly diagnosed form of cancer and "one of the deadliest".

"Awareness is the first step to early detection and improving cancer outcomes," Dr Schwartlander said.

"With few exceptions, early stage cancers are less lethal and more treatable than late stage cancers.

"Unfortunately, not all cancers are preventable — and improving early diagnosis and treatment services must therefore continue to be a focus of cancer control efforts."