Greek Prime Minister Alexis Tsipras reacts during a parliamentary session in Athens, Greece, July 16, 2015. [Photo/Agencies]

ATHENS - The Greek parliament passed sweeping austerity measures demanded by lenders to open talks on a new multibillion-euro bailout package to keep Greece in the euro, but dozens of hardliners in the ruling Syriza party deserted Prime Minister Alexis Tsipras.

The package was approved with 229 votes in the 300-seat chamber. There were 64 votes against it and six abstentions. But Tsipras required the support of pro-European opposition parties to push the measure through, leaving a question over the future of his government.

Tsipras said there was no alternative to the package, which he acknowledged would cause hardship, but he stood by the decision. "I am the last person to shirk this responsibility," he said.

In exchange for funding worth up to 86 billion euros, Greece has accepted reforms including significant pension adjustments, increases to value added tax, an overhaul of its collective bargaining system, measures to liberalise its economy and tight limits on public spending.

It has also agreed to sequester 50 billion euros of public assets in a special privatisation fund to act as collateral on the deal.

The measures were branded "social genocide" by the firebrand speaker of parliament Zoe Constantopoulou, one of 38 Syriza lawmakers to oppose the package, and there were violent clashes between protestors and police outside parliament as the debate went on before the vote.