Mumbai: The Indian rupee strengthened marginally against US dollar tracking gains in Asian currencies and ahead of Reserve Bank of India's bi-monthly policy due later on Friday.

At 9.10 am, the rupee was trading at 70.84 a dollar, up 0.09% from Thursday's close of 70.90. The Indian unit had opened at 70.88 a dollar.

According to a Bloomberg survey, RBI may lower its benchmark repurchase rate by 25bps to 5.15%. The central bank had lowered the repo rate by 35bps in August.

In pre-opening today, the benchmark Sensex index rose 0.69%, or 262.05 points, to 38,368.92. So far this year it gained 6.5%.

The yield on the 10-year Indian government bond was at 6.609% compared with its previous close of 6.613%. Bond yield and prices moves in opposite directions.

In the year so far, the rupee has weakened 2%, while foreign investors have bought nearly $7.94 billion in Indian equities and $3.89 billion in debt.

Asian currencies were trading higher as dollar dropped for fourth day amid speculation Friday's US payroll data will confirm the weakening trend seen in other economic numbers released this week.

South Korean won was up 0.68%, Taiwan dollar 0.37%, Indonesian rupiah 0.25%, Thai Baht 0.21%, Japanese yen 0.14%, Philippines peso 0.13%, China Offshore 0.09%, Singapore dollar 0.06%, Malaysian ringgit 0.05%.

The dollar index, which measures the US currency’s strength against a basket of major currencies, was at 98.841, down 0.02% from its previous close of 98.864.

(Bloomberg contributed this story)