China is sliding into recession and the leadership will not respond quickly enough with large-scale fiscal policies that could avoid a major slowdown and stimulate demand, Citigroup's top economist Willem Buiter said.

The only thing to stop a Chinese recession, which the former external member of the Bank of England defines as 4 per cent growth on "the mendacious official data" for a year, is a consumption-oriented fiscal stimulus program funded by central government and monetised by the People's Bank of China, Buiter said.

China's market volatility is putting global growth at risk, says the IMF. Credit:iStock

"Despite the economy crying out for it, the Chinese leadership is not ready for this," said Buiter, the man who coined the term "Grexit" during the Greek debt crisis.

China "is an economy that's sliding into recession," the renowned chief economist at Citigroup told a media call hosted Thursday by the Council on Foreign Relations in New York.