Greek lawmakers on Sunday adopted another batch of controversial spending cuts and tax hikes, two days before a crunch eurozone meeting expected to unlock the next tranche of much-needed bailout funds for the debt-ridden nation.

The 7,000-page bill that raises the sales tax cap and introduces a contingency mechanism to slash spending further in case of budget overruns was passed thanks to the Syriza-led coalition government's slim majority in the 300-seat parliament, according to an AFP count.

All 153 of the coalition's MPs voted in favour, while outside the parliament building in Athens more than 10,000 people protested against the unpopular reforms.

Syriza MP Vassiliki Katrivanou, however, voted against several of the bill's articles and later resigned from the party, citing a "deep political and existential impasse".

"We (Syriza) implement measures and policies that are against the core of our values and also of our politics but I cannot think of any other trustworthy alternative. That's why I resign," she wrote on Facebook, handing her seat back to the party.

She had voted for the bill overall but against the articles calling for the contingency mechanism and the creation of a state privatisation fund.

The so-called contingency mechanism, labelled "the cutter" by Greek media and designed to cut spending if the country fails to meet fiscal targets in 2018, is of chief interest to Greece's international creditors.

"European leaders get the message that Greece is sticking to its promises. Now, it's their turn," Greek prime minister Alexis Tsipras said ahead of the vote.

- 'It's raining taxes' -

People across Greece's political spectrum have criticised the massive bill, the latest in a series of sweeping reforms for the austerity-weary nation.

"No one in Greece will remain unaffected by the typhoon of the new measures," Kyriakos Mitsotakis, the leader of main opposition party New Democracy said in parliament.

Greek newspapers on Sunday complained that the new measures -- including a top rate sales tax increase from 23 to 24 percent -- did not come with a promise of debt relief from the country's international creditors.

"It's raining taxes, with the future of debt uncertain," read a headline in Kathimerini newspaper.

"The measures we are talking about aren't pleasant. Especially for citizens that have already endured a lot," Prime Minister Alexis Tsipras admitted on Sunday.

But he said "this is the first time that the sacrifices seem to have a prospect of paying off".

Greece and its European Union creditors are locked in talks on how to reduce the country's debt burden, which the International Monetary Fund (IMF) said must happen if it is to contribute any more of its own funds.

The IMF said Thursday that Greece would need a lengthy period free from debt payments to achieve sustainable finances if the bloc does not agree to cutting the debt up front.

"It is possible to restore debt sustainability without up-front haircuts, although this would involve providing very concessional loan terms including long grace and maturity periods and very low interest rates," IMF spokesman Gerry Rice told reporters.

- Debt relief on the table -

As for the IMF's participation in the rescue, Rice said the global emergency lender is still assessing the reforms Athens is undertaking to strengthen its finances.

"We don't want more austerity for Greece and we certainly don't want more of the burden to fall on the poor and the most vulnerable," he said.

The Greek government, at loggerheads with its creditors as it seeks to obtain some relief, appears confident.

But EU economic powerhouse Germany has been deeply opposed to alleviating any of Athens' debt.

It believes Greece should be granted relief only in 2018, once it has fully complied with the EU bailout, according to a finance ministry document seen by AFP Thursday.

Eurozone finance ministers are set to discuss easing Greece's debt burden and disbursing the next round of funds at a closely-watched Eurogroup meeting in Brussels on Tuesday.

Greece urgently needs the next tranche of bailout money to repay big loans to the European Central Bank (ECB) and IMF in July, and has already fallen behind in paying for everyday government duties and public sector wages.

German financial daily Handelsblatt has said Athens could receive between nine and 11 billion euros if a deal is struck this week.