WARSAW (Reuters) - Poland’s ruling Law and Justice party (PiS) says ‘no’ to the euro and believes Warsaw should only adopt the common currency when its economy is as big as Germany’s, PiS leader Jaroslaw Kaczynski said on Saturday.

FILE PHOTO: Jaroslaw Kaczynski, leader of the ruling Law and Justice party (PiS), delivers a speech during the party's convention in Warsaw, Poland September 2, 2018. REUTERS/Kacper Pempel/File Photo

Kaczynski was speaking at a PiS convention in Lublin, eastern Poland, ahead of the European Union election in May, which is seen as a test for the party and its major opponents ahead of a general election in Poland later this year.

“We say ‘no’ to the euro, ‘no’ to European prices,” Kaczynski said. “We will adopt the euro someday, because we are committed to do so and we are and will be in the European Union, but we will accept it when it is in our interest.”

“It will be in our interest when we reach a level very close to Germany (in) GDP level, standard of living.”

Poland is obliged under its EU accession commitments to join the euro zone at some point.

PiS has said previously that Poland should not hurry to join the currency bloc, but it is now reiterating the argument to attract more supporters ahead of the vote.

While most Poles support Poland’s membership of the EU, they are not so unanimous over the euro, opinion polls suggest.

PiS has the backing of 38.7 percent of the electorate, while the European Coalition has 36.2 percent, an opinion poll by pollster IBRIS for private radio station ZET showed on Saturday.

The European Coalition consists of the leading opposition parties, including PiS’ biggest political foe the Civic Platform, which united earlier this year against the ruling party.

PiS has prevailed in most polls since taking power from the Civic Platform in 2015.

The Coalition has not publicly declared its policy on joining the euro, though it is widely seen as taking a more positive stance than PiS.

Civic Platform was co-founded by European Council president Donald Tusk, a supporter of the single currency before the euro zone financial crisis, but the party has said Poland needs a debate on adopting the euro.

PiS has seen its popularity erode after a series of scandals, with local media accusing the party of allowing excessive pay at the central bank and running a murky real estate business. PiS denies any wrongdoing.