Rising aversion in Poland towards the European Union is worrying, the country's outgoing central bank governor told CNBC, at a time when Euroskepticism appears to be rising across the region.

Poland is a member of the 28-country EU, with which Poland's ruling Euroskeptic Law and Justice Party has clashed since taking power in October. The Polish government has increased its power over domestic institutions and the EU is investigating whether its changes to the Polish constitutional court undermine the rule of law.

The highly conservative party has also removed the EU flag that previously appeared in the backdrop of the prime minister's media conferences and said it would not take part in a mooted EU scheme to share refugees between member countries.

Marek Belka, the governor of the National Bank of Poland, described the flag move as "rather silly."

"We do not need gestures that are anti-Europe," he told CNBC on Wednesday.

"These types of gestures may backfire in serious discussions (with the EU) about money or about regulations. So of course I am sort of concerned," he said later.

Poland has a history of Euroskepticism and was equivocal on joining the single currency even before the euro zone debt crisis of 2010 onwards. It continues to use the Polish zloty (Exchange: EURPLN=).

Belka said Poland did not feel under pressure from euro zone members — which include Germany, the country's major trading partner — to adopt the euro (Exchange: EUR=) in the near-term, even though it has committed to doing so at some point.

"Everybody understands this (the euro zone) is a project that still has unresolved dimensions and issues," he told CNBC.

Belka replied "of course not" when asked if it had been appropriate to allow Greece to join the euro in 2001, giving its financial situation.

"It is obvious; it has always been obvious that the whole 'Operation Greece' should have started with massive debt reduction, which was not the case," he said.

Greece has received repeated bouts of aid in the wake of the euro zone debt crisis. Early on Wednesday, euro zone finance ministers agreed to give the country another $11.4 billion in exchange for further reforms and austerity measures. However, euro zone leaders, led by Germany, have resisted calls from the International Monetary Fund to provide Greece with upfront, unconditional debt relief.

Anti-EU sentiment seems to be rising in several countries in the union. Austria was close to appointing a Euroskeptic — and far-right — president this week and the U.K. will hold a referendum next month on quitting the EU, which is seen as being closely-fought.