The European Central Bank is increasingly concerned by a deteriorating relationship between the Greek government and the country's central bank, according to sources.

Recent government comments targeting the Bank of Greece have been noted at the Frankfurt-based ECB, which is responsible for monitoring the legally mandated independence of central banks in the European Union.

The ECB may issue formal warnings to the Greek government if the situation worsens, the sources said.

An ECB spokesman declined to comment immediately.

The government has accused Bank of Greece governor Yannis Stournaras of attempting to undermine the administration through leaks to the media as the country negotiates with its creditors to try to avoid a default.

The Greek central bank has denied sending an anti-government e-mail to a journalist. Mr Stournaras was finance minister in the previous Greek government.

The ECB has intervened in recent cases where members of its Governing Council, which is comprised of representatives from the euro-area’s 19 members, have complained of bullying from their government.

In 2013, ECB president Mario Draghi complained to the government of Cyprus after a spat between Governing Council member Panicos Demetriades and president Nicos Anastasiades. Mr Demetriades later resigned. – Bloomberg