The bank is scheduled to hold its next monetary policy committee (MPC) meeting on Thursday and is expected to stick with a tighter stance to fight inflation -- at 18.91 percent in October -- and foreign exchange volatility.

The bank aggressively raised its benchmark rate by 9.5 percentage points to 16.5 percent in the last two policy meetings, causing an acute funding squeeze that helped the shilling recover 15.4 percent from a record low of 107 hit on Oct 11.

At 0714 GMT, commercial bank quoted the shilling at 90.50/70 against the dollar, weaker than Friday's close of 90.30/50.

"We've seen early demand from the energy sector," said Chris Rwengo, head of trading at Standard Chartered Bank.

Traders said they expected the shilling to trade in the 90.00-91.00 range during the session.

Some traders said the shilling weakness could also be exacerbated by a globally stronger dollar triggered by worries over the impact of worsening debt problems in the euro zone.