The EU leaders see the UK's vote to leave the bloc as "politically binding," Oettinger told German newspaper "Bild" in an interview published on Tuesday.

Still, "it could be that public opinion shifts if the economic situation worsens because of the Brexit vote," he added.

"In any case, I wouldn't bet big money on Brexit," Oettinger said.

The German conservative has served as the Commissioner for Digital Economy and Society in the European bloc since 2014. He was previously the bloc's Energy Commissioner.

London in the doorway

The UK voted against the EU in the June 23 referendum. However, London has still to trigger the formal procedure on cutting ties with the bloc. Most analysts expect the move to extend a period of economic uncertainty.

On Tuesday, German Foreign Minister Frank-Walter Steinmeier said that Brexit would have long-term consequences that were still difficult to estimate. Both London and Brussels needed "new, fair and binding" rules for their future relations, he added.

British Prime Minister Theresa May is expected to discuss the exit talks with her cabinet on Wednesday.

Turkey to join EU 'after Erdogan'

In the Bild interview, Oettinger also said that London's hesitation in starting the talks would increase economical and political uncertainty.

Commenting on the future of the bloc, Oettinger also remarked on Turkey's bid to join the EU. This goal was was "not realistic until well into next decade" he told the mass circulation newspaper. "It is likely a topic for the time after Erdogan," he added.

Even so, it was important to maintain good relations with Ankara due to Turkey's geopolitical and economic status, according to the European politician. Turkey plays a major role in the transit of refugees heading to Europe.

No 'leeway' on anti-terror law

Under the conditions of the refugee deal Turkey was promised visa-free travel. Ankara claims it has done enough to win this EU concession by October.

Turkish politicians have openly threatened to abandon the refugee accord if the EU decides to keep its visa requirement for Turkish residents.

Oettinger believes that there is still work to be done before waiving the visas, especially with Turkey's approach towards fighting terrorism. The country's anti-terror law has been used to target academics and journalists.

"Most importantly, we cannot give any leeway when it comes to anti-terror laws in Turkey," Oettinger said. "If Turkey needs more time to change the law, so be it."

dj/jm (AP, Reuters, dpa)