Polish President Lech Kaczynski vetoed a bill on Monday that would cut early retirement for 750,000 people amid pressure from trade unions.

The lower house of parliament approved the bill last month, which would reduce the number of people eligible for early pensions from more than 1 million to some 250,000.

"On the basis of arbitrary criteria ... for some it gives early pensions while not for others," Kaczynski said, calling the bill "unjust."

The ruling Civic Platform party proposed the retirement cuts to balance the budget and ensure pensions for future generations. There are now five workers for every retiree, the daily Wyborcza has reported, but by 2050 that number will shrink to two workers per pensioner.

The proposed bill caused an uproar among Polish trade unions, who had recently threatened a general strike. Some 30 union members had occupied the Prime Minister's office last month, demanding to talk with PM Donald Tusk and refusing to leave until they got a meeting.

The bill will now return to the Polish parliament, which to reverse the veto needs a 3/5 majority vote.