Risks to China's economy could drag 2014 GDP to its lowest level since 1990 before stimuli from structural reforms start to have an effect, economists say.

Qu Hongbin, chief economist in China at the British bank HSBC, expressed his concerns on Tuesday in Beijing about a further slowdown of the world's second-largest economy, as reform plans raised by the Third Plenum of the 18th Central Committee of the Communist of China in November could be slow to show results.

He forecast that the GDP may increase by about 7.7 percent this year or even as little as 7.5 percent, which would be China's slowest annual growth since 1990.

According to the data release schedule, the National Bureau of Statistics will report the annual GDP and other economic indicators for 2013 on Jan 20.

Qu noted that while reform measures might not bring obvious changes until 2015, China's economic growth should rev up again after that.

"The major threats to China's economy are the rapidly expanding shadow banking system and the faster-than-expected growth of local government debt, although the risks remain under control so far," he said.

The two factors reflect excessive or inadequate expansion of the virtual economy, according to Qu, and could impair the development of the industrial, or "real" economy, if fiscal reforms don't provide a solution soon.

The leadership's cautious attitude toward local government debt supervision and banking loan regulations may restrain fixed-asset investment in the short term.

In the meantime, domestic demand will be under pressure. The central government's campaign to curtail departmental spending on receptions, vehicles and overseas trips will continue, and will chill the rise of consumption to some extent.

One positive factor is that the United States and eurozone seem set to recover in coming months, driving a rise in China's exports from external demand, Qu added, "but the improvement will be moderate, and it is not likely to bring large stimulation for China's economy."

On the same day, JPMorgan Chase's Managing Director and Vice-Chairman of Asia Pacific Jing Ulrich gave a more unsettling prediction of 7.4 percent for 2014.

But she said she expects additional reform policies to be written this year, including ones to reduce overcapacity and support service industry development. Such reforms will benefit the country in the long run, she said.

Another 2014 forecast came Tuesday from Citibank (China) Co Ltd, which predicted China's GDP growth to reach 7.6 percent.

"China will sacrifice some of its economic growth momentum for reform," said Oliver Chiu, head of research and investment advisory for Citibank (China). "Sustaining investment and economic restructuring will take place at the same time so that growth is mild but stable."

The stock index will rise to 2,700 by the end of this year from its current 2,000, Chiu said, due to the restart of initial public offerings and the expansion of the National Equities Exchange and Quotations, or so-called Third Board.

"China's stocks will rebound after years of ranking at the bottom among major world stock exchanges," said Chiu. "The reform measures will allow creative companies with higher growth potential to flourish and cast out those with low returns."

The United States' quantitative easing will continue to taper down until it draws to a complete close at year-end. But interest rates likely won't be raised until March 2015.

The withdrawal of QE is unlikely to trigger a serious credit crunch in emerging economies, as happened during the Asian financial crisis of 1997, because of the large amount of foreign reserves held by these developing countries.

The world economy will gradually recover from its latest financial crisis, according to Citibank (China). Global GDP will increase from 2.4 percent in 2013 to 3.1 percent in 2014, its highest level since 2010, Citibank's report said.