* Median 40 percent chance ECB buys sovereign bonds
* ECB to buy 400 bln euros of ABS and covered bonds
* Latest round of policy will be effective in lifting inflation
By Jonathan Cable
LONDON, Sept 4 (Reuters) - The European Central Bank will probably not buy sovereign bonds as the 400 billion euros it is expected to spend on an asset purchase scheme announced on Thursday will be enough to drive up inflation, a snap Reuters poll found.
ECB President Mario Draghi told a press conference on Thursday the bank would buy asset-backed securities (ABS) and covered bonds in its latest attempt to push money into the flagging euro zone economy. At a policy meeting earlier, the bank cut interest rates to new record lows.
The bank will purchase around 400 billion euros of assets, taking a year or two to do so, the poll of 40 economists taken after the press conference said.
Sources told Reuters earlier on Thursday that the purchases could amount to 500 billion euros over three years.
Euro zone inflation fell to just 0.3 percent in August, well below the ECB's target of just under 2 percent and what it terms the "danger zone" of 1 percent, while growth flatlined last quarter - even before the effects of the Ukraine crisis are felt.
Still, those latest measures should be effective in driving inflation back to target, according to almost three quarters of the respondents in Thursday's poll.
"I don't think it's a panacea but I think it has some influence," said Richard Kelly at TD Securities. He was one of only three of 44 economists in a Reuters poll taken ahead of the policy meeting to correctly predict the rate cuts.
"Even if it doesn't necessarily get lending going - at the end of the day you need growth in the euro zone to see that happen - this can help due to confidence measures and that's what you are trying to drive."
Traditional methods of quantitative easing, like those conducted by the U.S. Federal Reserve and the Bank of England, involve buying government bonds, but an ECB source told Reuters last week that for the ECB "the barrier to QE is still very high".
The poll gave only a median 40 percent chance the ECB would eventually buy sovereign bonds.
Highlighting its concern about the currency bloc's health, the ECB cut its main refinancing rate by 10 basis points to 0.05 percent and reduced its deposit rate by the same margin, sending it to minus 0.20 percent - effectively increasing what it charges banks to park funds with it.
The interest rate cuts make the ECB's upcoming four-year loan offer to banks, or TLTRO, due to launch later this month, more attractive as banks can get the funds for less. However, Thursday's poll said only about 275 billion euros of the 400 billion available would be borrowed.
That is far less than the 363 billion euros a July 28 poll of money market traders expected and shy of the 300 billion euros predicted in a July 30 Reuters poll of economists.
"TLTRO take-up will be less than expected now. The ABS programme cannibalises the TLTRO - if you buy all the ABS bonds and then ask them to take loans, what will they keep as collateral?" said Christian Shultz at Berenberg. (Additional reporting by Deepti Govind and Ashrith Doddi; polling by the Bangalore Polling Unit; Editing by Susan Fenton)