EU funds support the roughly 3.5 million Syrian refugees in Turkey, after Syria's more than eight year war killed hundreds of thousands and pushed millions from their homes. In turn, Turkey has agreed to halt further immigration to Europe.
"The flow of funds should be sped up and the amount of funding should be increased," said Faruk Kaymakci, a deputy Turkish minister of foreign affairs.
"As long as the crisis is there we have to work together. The 6 billion euros will not solve the problem when it is finally all spent," Kaymakci told reporters in Istanbul.
The EU, which set up the funding in 2015, says more than 5.6 billion euros have been allocated, more than 3.5 billion contracted and more than 2.4 billion disbursed.
Kaymakci said hosting the refugees costs Turkey some $40 billion in total.
Europe's relations with Turkey are strained on several fronts including disagreement over a Turkish military incursion in October against a Kurdish militia in northeast Syria.
Turkey in late October threatened to "open the gates" to allow refugees into Europe unless Europeans back its plan to resettle them in northeast Syria.