"We cannot accept an understanding like 'give us the money and they stay in Turkey'. Turkey is not a concentration camp," Davutoglu said in a live television interview a day after meeting with German Chancellor Angela Merkel on the migrant crisis.
"I said this to Merkel too. No-one should expect Turkey to turn into a concentration camp where all the refugees stay in," he said.
"We spoke of three billion euros (USD 3.4 billion) as 'fresh money' but it is not a fixed sum. Our (financial) needs may increase," Davutoglu said.
Merkel yesterday had hailed progress on an EU-driven "action plan" after talks in Istanbul with Davutoglu and President Recep Tayyip Erdogan.
Brussels has offered Turkey financial help and an acceleration of its drive for EU membership among other sweeteners to persuade it to do more to tighten its border security.
More than 630,000 people fleeing war and misery have landed on Europe's shores so far this year, many making risky sea crossings from Turkey to Greece.
