China is widely expected to leave lending benchmark rates unchanged at a monthly fixing on Wednesday, a Reuters survey showed, as fresh signs of economic stabilisation and a weakening yuan constrained further monetary easing efforts.

The loan prime rate (LPR) normally charged to banks' best clients is calculated each month after 18 designated commercial banks submit proposed rates to the central bank, the People's Bank of China (PBOC).

In a poll of 29 market analysts and traders, all participants predicted the one-year LPR would stay unchanged at 3.45%, after the central bank kept the medium-term policy rate steady last week.

For the five-year tenor, 26, or about 90% of all respondents, expected it to remain unchanged at 4.20%, while the other three participants forecast a marginal reduction of 5 to 10 basis points.

Most new and outstanding loans in the world's second largest economy are based on the one-year LPR, while the five-year rate influences the pricing of mortgages.

The medium-term lending facility (MLF) rate serves as a guide to the LPR and markets mostly use the MLF rate as a precursor to any changes to the lending benchmarks.

China cut the one-year benchmark lending rate in August but surprised markets by keeping the five-year rate unchanged amid broader concerns about a rapidly weakening currency.

Lin Li, head of global markets research for Asia at MUFG Bank, said both one-year and five-year LPRs are likely to remain steady as a weakening yuan in light of widening yield differentials with other major economies could still restrain the room for monetary policy maneuvers.

"The already large negative yield spreads over the U.S. limit the room for rate cuts this month," Li said in a note.

"While the August data helped to boost yuan sentiment, we think a turnaround will still depend on more data supporting a stronger economic recovery and improving yield differentials."

The yield gap between China's 10-year government bonds and their U.S. counterparts stood at 163 basis points on Tuesday, not far from the widest level in 16 years hit in late August, of 171 basis points.

The widening yield differentials have dragged the Chinese yuan down by more than 5% this year to become one of the Asia's worst performing currencies.

A string of economic data including August credit lending growth, factory output and retail sales showed the world's second-largest economy was picking up steam.

China's central bank last week lowered the amount of cash that banks must hold as reserves for a second time this year to boost liquidity and support economic recovery.

(Reporting by Shanghai Newsroom Editing by Bernadette Baum)