Hong Kong has fallen into recession, hit by more than five months of anti-government protests that show no signs of relenting, and is unlikely to achieve annual economic growth this year, the city's Financial Secretary said.

"The blow to our economy is comprehensive," Paul Chan said in a blog post on Sunday, adding that a preliminary estimate for third-quarter GDP on Thursday would show two successive quarters of contraction — the technical definition of a recession.

He also said it would be "extremely difficult" to achieve the government's pre-protest forecast of 0 to 1 percent annual economic growth.