Andrzej Duda, the Polish president | Toms Kalnins/EPA Poland’s Duda vetoes change to European election rules Critics say planned change would have resulted in just two parties being able to win seats in next year’s European election.

WARSAW — Polish President Andrzej Duda on Thursday refused to sign into law a change to the way the country elects members of the European Parliament, which critics say would have squeezed out all but the largest parties.

The proposed change — which he said would have raised the election threshold to over 16 percent — is going "back to parliament for reconsideration," Duda told reporters shortly before setting off on an official trip to Australia.

"The proposed law goes too far from the required rule of proportionality," he added. "Its introduction would result in a large number of citizens not having their representatives in the European Parliament [and] would result in a low turnout due to citizens' discouragement."

The law was pushed through parliament in July by the ruling Law and Justice party (PiS) but came under attack as it could have resulted in Poland's 52 seats in the European Parliament being shared out only between the two largest parties — PiS and Civic Platform — in next year's ballot. The government said it would have simplified a complex and outdated voting system.

According to experts in the Polish Senate, the change would have made it necessary for parties to receive 16.5 percent of the vote to get a European lawmaker elected (the threshold set by European law is 5 percent). According to Bartłomiej Michalak, of the Batory Foundation, a Polish NGO, the new electoral threshold would be between 9 and 20 percent.

Duda said the existing voting system needs to be reformed as it's too complicated and not proportional enough.

"The simplification of the existing system is possible and if I get such a bill, I'll gladly sign it into law," the president said.

Duda, who was a PiS candidate in the presidential election of 2015, has vetoed a small handful of legislation pushed through parliament by PiS, including two controversial bills on reforming the judiciary.

Duda eventually signed the judicial laws after cosmetic changes which gave him more say in nominating senior judges. But the amended laws still include a provision under which Supreme Court judges may be removed in the middle of their term. The European Commission on Tuesday moved a step closer to asking the European Court of Justice to penalize Poland over the law.

Political scientist Marek Migalski told news channel TVN24 he believes Duda used the veto after consulting with his political mentor Jarosław Kaczyński, the powerful chairman of PiS.

“They realized that the new rules may prompt opposition parties to create a large coalition which would be able to crush PiS in the vote,” Migalski said.