China's outstanding corporate debt will catch up and surpass the United States to become the largest globally within the next two years, said Standard & Poor's Ratings Services in a report released on Tuesday.

"We expect the debt needs of China, with its higher nominal GDP growth rate, to reach $18 trillion over the next five years ending 2017 — a significant share of the estimated $53 trillion of global refinancing and new money requirements over this period," said the international ratings agency.

Of the $49 trillion-$53 trillion in financing that non-financial corporates will need from 2013-2017, outstanding debt to be refinanced accounts for about $34.7 trillion, and new money that borrowers will seek to fund growth makes up $14.7 trillion-$18.7 trillion, it said.

The developed Western economies of the US, Canada, the eurozone, and the United Kingdom account for about $18 trillion, or 53 percent, of the refinancing amount. Of the Asia-Pacific region's almost $16 trillion refinancing need over the five-year period, China's $8 trillion accounts for about half, according to the report.

Within the next five years, China's economic expansion could see its non-financial corporates looking for $16 trillion-$18 trillion in financing. As it stands, the country's credit boom has resulted in outstanding corporate debt of 134 percent of GDP, said S&P.

It added that China's surging corporate credit is mainly attributable to high levels of investment, primarily in manufacturing, real estate, and infrastructure, and credit growth that fuels the investment.

"Absent a more substantial rebalancing of the economy toward consumption, away from investment, China's corporate debt growth is likely to continue at a fast pace for the foreseeable future."

But among a sample of 32 economies, China has the highest risk of an economic correction because of low investment productivity, it said.

And a fairly quick rise in banks' non-performing loans above currently manageable levels might be triggered by an attempt to rebalance the economy to depend less on investment and more on consumption, as government policy may cause investment to scale down faster than consumption can compensate for the slack, said the report.