Poland’s lower house of parliament has approved EU borrowing plans to finance the bloc’s €750bn pandemic recovery fund, despite deep divisions over the proposal in the ruling conservative-nationalist coalition.

The recovery fund is the central plank of the EU’s efforts to repair the huge damage to its members’ economies caused by the impact of Covid-19, but the aid cannot be disbursed until all the bloc’s 27 states have ratified an increase in the EU’s so-called “own resources” that will finance it.

More than a dozen EU states have already done so. But in Poland, the ruling Law and Justice party (PiS) has spent the past few weeks scrambling to cobble together a parliamentary majority in favour of the “own resources” increase, after one of its two smaller coalition partners, United Poland, said it would vote against the plan.

PiS’s leader Jaroslaw Kaczynski warned last month that the ruling coalition could collapse if United Poland’s stance meant that the “own resources” bill was rejected, raising the prospect of early elections.

However, after the second-biggest opposition group, The Left, said it would back the bill, Polish MPs approved it in a special session on Tuesday, with 290 voting in favour, 33 against and 133 abstaining. The bill must now also be considered by the upper house of parliament, the Senate, and signed off by the president.

Poland is set to be one of the biggest beneficiaries of the EU recovery fund, receiving at least €36bn in grants and loans. Prime minister Mateusz Morawiecki said approving the plan was “one of the most important decisions” the country would make “for the next 10, 20 years”.

“These are funds that will decide on the advance of Poland,” he said as he urged MPs to back the plan during the Sejm debate.

However, his arguments were not enough to win over United Poland, led by hardline justice minister Zbigniew Ziobro, which followed through on its pledge to vote against the “own resources” legislation, underscoring tensions within the ruling coalition that have become more public in recent months.

United Poland fears the bill would leave Poland on the hook for other EU member states’ debts. It also objects to plans to link access to EU funds to respect for the rule of law, which it says could be used to “blackmail” Warsaw, which has spent much of the last five years at loggerheads with Brussels over a series of controversial changes to Poland’s judiciary.

The vote also split Poland’s opposition. Civic Coalition, the largest opposition group, had long warned that it would not back the “own resources” bill unless PiS provided guarantees that EU funds would be spent fairly and transparently.

Nearly all of Civic Coalition’s MPs abstained from the vote after a series of amendments it had proposed were rejected. Its leader, Borys Budka, said PiS had provided no guarantees that local authorities would have a say in how EU funds were spent, and attacked The Left for helping PiS pass the bill, accusing it of “defection”.

However, Adrian Zandberg, one of the leaders of The Left, said “the obligation of responsible politicians” was to “secure the funds” for Poland.

“The European recovery fund is a second Marshall Plan,” he said, referring to the US-led recovery programme launched to help rebuild western Europe in the wake of the second world war.

“But unfortunately it is not guaranteed that everyone will take part in this great project. And that has already happened once. Poland [didn’t] take part in the Marshall Plan. And we are still paying for that today.”