BRUSSELS (Reuters) - EU competition regulators temporarily cleared 18 billion euros ($22 billion) in state aid for four of Greece's largest banks -- National, Alpha, EFG Eurobank, Piraeus -- and said they would assess the support to see if it gives them an unfair advantage.

The bridge recapitalization was granted by the Hellenic Financial Stability Fund in April as part of the banks' planned share capital increases.

The European Commission said on Friday it had approved the aid for six months, while it waits for the Greek authorities to present details of the conversion of the bridge recapitalisation into a final recapitalization.

The EU watchdog said it would study the aid to see if it was in line with EU state aid rules.

Separately, the Commission also cleared 1.7 billion euros of public support to wind down Proton Bank. It will now investigate the restructuring plan for the new group created from the remains of that bank.

($1 = 0.8130 euros)

(Reporting by Foo Yun Chee; editing by Rex Merrifield)