Frankfurt: The European Central Bank is likely to extend banks' access to unlimited funds at fixed interest rates into the start of the third quarter at its March 4 meeting, as worries about Greece and sluggish growth weigh on financial markets, euro zone monetary sources told Reuters.

However, discussions with officials over the last two weeks show views are split over whether the extension of such funds should cover just the main weekly liquidity operations or longer-term loans as well, also revealing differences on how soon to raise interest rates.

Unlimited access to cheap cash has been at the heart of the ECB's efforts to support banks through the financial crisis and analysts expect it to return to pre-crisis mode with liquidity measures before raising interest rates.

The bank has promised to give more details on phasing out the measures at its March 4 meeting and markets expect it to take further small steps, although they hope the bank will extend full allotment in some form.

The sources said some policymakers would prefer longer-term loans to return to a normal auction procedure as early as the second quarter, although the ECB is aware of the need to smooth the repayment of close to half a trillion euros in 12-month funds on July 1.

"It is important that when the 12-month tender matures, that we have additional tools at our disposal in order to cope," a senior Eurosystem official said.

Other central bank insiders who spoke to Reuters on condition of anonymity said renewed market tensions in the wake of Greece's debt problems which have pushed up yields on several countries' sovereign bonds argued for extending the status quo for another three months.

"I would not rule out that we leave things as they are in March, considering the Greek situation and the tensions on markets," another euro zone central banking source said.

A third central bank source said the fact that recovery in Germany, the bloc's biggest economy, faltered in the fourth quarter did not bode well for the future.

"Under today's conditions, with Germany reporting almost zero growth, it's not really the time to be changing anything," this euro zone source said.

The ECB has promised to lend banks all the funds they need at fixed rates at its weekly operations until April 13, and at one-month and three-month operations until the end of March.