The Turkish currency was under pressure on Wednesday despite a decision by the central bank on Tuesday to raise its overnight rate by half a point to 7.75 percent.
The lira fell to 1.9572 to the dollar from 1.9492 at the close on Tuesday.
The lira has fallen by about 10 percent since February, when it was at a 12-month peak of 1.7460 lira to the dollar.
But it is still slightly above a 12-month low of 1.96590 lira to the dollar set in early July, forcing the central bank to take urgent measures.
The central bank's decision to raise its overnight rate follows recent intervention to defend the lira and is the latest sign of turmoil in emerging markets.
In a written statement on Wednesday, central bank governor Erdem Basci said: "The additional monetary tightening will be maintained everyday until further notice."
Basci also said the bank would sell a minimum of $100 million in foreign exchange auctions.
"As of today, a minimum of $100 million will be sold at 1630 local time (1330 GMT) on days when additional monetary tightening is applied," he said.
In July, when the lira fell heavily, the central bank announced urgent action to tighten monetary policy, curb credit and to use foreign reserves to buy the lira on the foreign exchange market which it did using substantial amounts.
The central bank also announced in July that the primary dealer rate would not be available on the days when additional monetary tightening was applied.
Analysts say Basci's announcement suggests that the primary dealer lending rate would not be available for indefinitely, adding that the 7.75-percent rate would constitute an effective ceiling until the additional tightening policy achieves the central bank's goal.
"Today's statement shows that the central bank is indeed willing to implement exceptional days frequently. We think this decision is positive to support TRY (lira) as it makes the O/N (overnight) lending rate a credible threat against short TRY positions," said Deniz Cicek, economist at Finansbank.
This was a reference to the way an increased overnight rate raises the cost and risk for market operators who borrow lira to take positions which will yield a profit if the lira falls further.
"However, we are not sure the current level of the ceiling will be sufficient to contain depreciation pressures should the sentiment towards EMFX gets even worse," Cicek warned.
He added that the central bank's measures would probably not be enough and that the overnight rate may have to be raised again.
He said that the sale of foreign exchange through auctions would probably not be enough to halt the selling of lira.
"Therefore, we continue to expect more ceiling hikes (in the rate) to come in coming months, which is likely to push the O/N lending rate to 9.0 percent."
Turkey is vulnerable to the recent slowdown in capital inflows and analysts say the economy is likely to take a hit from external financing conditions and particularly the changes in US monetary policy.
Capital Economics, in London, said in a statement that central European currencies may see some small losses this year.
"We're more downbeat on the outlook for the Turkish lira and Russian ruble. For the former, we think rising external financing needs will keep the lira under pressure and we expect it to drop to 2.05/US$ by end-2014 (currently 1.95/US$)," it said.
Analysts also express concern about the extent to which the Turkish economy is dependent on credit, and also about a deficit on the balance of payments current account.
The government was predicting far slower growth of 4.0 percent this year, half the rate two years ago.
But Finance Minister Mehmet Simsek has recently said the government might even have to lower that estimate owing to US monetary policy and recession in the eurozone.