Turkey's central bank is expected to ignore political pressures and hike its lending rate to around 10% at an emergency meeting today.
However, it is unclear whether that would be enough to stem a slide in the lira.
Prime Minister Tayyip Erdogan has been a vociferous opponent of higher borrowing costs, railing against what he describes as an "interest rate lobby" of speculators seeking to stifle growth and undermine the economy.
That has left the central bank struggling to contain the lira's precipitous slide as a corruption scandal shaking the government and fears about a power struggle and the impact of a cut in US monetary stimulus shake investor confidence.
The central bank is expected to raise its overnight lending rate by 225 basis points to 10% today at its first extraordinary monetary policy meeting since August 2011, at the height of the euro zone debt crisis.
This is according to the median forecast in a Reuters poll of 31 economists.
30 of those polled from a wide sample of Turkish and international banks forecast a hike, with estimates ranging from a rise of 125 basis points to 425. Only one forecast the bank would leave rates unchanged.
There was less consensus over whether such a move would be enough to stabilise a tumbling lira and rising inflation, with only 12 economists saying yes and seven saying no, citing the need for structural reforms and political stability.
The graft scandal, which triggered the resignation of three ministers and detention of businessmen close to Erdogan, has grown into one of the biggest challenges of his 11-year rule.
His reaction, purging the police force of thousands of officers and seeking tighter government control over courts, has drawn criticism from the EU and raised investor concern over the rule of law and independence of state institutions.
The lira's dive means Turks now need more than twice as many lira to buy dollars as they did at the currency's peak six years ago, a stark fall in a land heavily dependent on imports.
It has also badly exposed Turkish firms with foreign debts, forcing them to scrap some investments, and has dented profits made by foreign companies in Turkey.
The lira edged back from record lows after the central bank announced its emergency policy meeting yesterday, raising market hopes for a decisive rate hike.
The bank said it would issue a statement on the outcome later tonight.
Fearful up to now of an outright rate hike, it has been struggling to defend the lira instead by burning through its foreign currency reserves and trying to squeeze up borrowing costs on the margins - a battle it has clearly been losing.