Analysts estimate around 200 million dollars of reserve losses in January and a higher volume since then.
Gilt-backed repos traded around 8.95/9.00 percent and call money traded around 10.00 percent.
On Thursday call rates hit double digits for the first time during the current balance of payments crisis began and rates rose as much as 10.25 percent Friday according to Central Bank data.
On Thursday banks borrowed 10 billion rupees from a liquidity auction at an average rate of 8.89 percent and 10.15 billion rupees from the Central Bank's 9.0 percent reverse repo liquidity window.
On Friday banks borrowed 8.0 billion rupees from an auction at an average 8.9 percent and 9.6 billion rupees from the window. Some banks however had excess liquidity of 9.9 billion rupees.
On Monday the spot US dollar was quoted at 121.70/122.20 rupees after opening at 121.30/80 levels, dealers said.
Large liquidity shortages are generated from Central Bank forex sales to banks to defend a dollar. The Central Bank 'sterilizes' the interventions through liquidity injections to prevent interest rates from going up too much.
The rupee injections, which increase the ability of banks to give fresh loans, fire new demand in the economy, putting yet more pressure on the dollar peg and foreign reserves.
Sri Lanka runs into balance of payments crisis, because the country has a dollar 'soft-peg' where the Central bank tries to control both the interest rate and exchange rate at the same time.
The current crisis was triggered by high credit growth from mid 2011 when the state started subsidizing thermal power generation with state bank credit. Power and fuel prices were raised in February.
Thought the central bank halted major interventions in the forex markets from February 09, it planned to spend around 850 million dollars in interventions in the ensuring three months.