Update: Greece’s parliament passed the bailout measures shortly after the deadline of 8am Australian Eastern Standard Time

Greece’s deputy finance minister Nadia Valavani has resigned as the parliament readies to vote on unpopular reforms needed to unlock a huge bailout from eurozone creditors.

“I’m not going to vote for this amendment and this means I cannot stay in the government,” Ms Valavani told reporters.

She submitted her resignation in a letter to Prime Minister Alexis Tsipras.

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On Wednesday, pharmacists and civil servants went on a strike to protest against the tough bailout reforms that are due to be passed in parliament.

Politicians are due to vote on the measures which are key to unlocking the aid Greece needs to stay afloat, but which are hard to accept for many in a country which has been plagued by economic problems due to austerity.

Protesters chant slogans during a protest march in central Athens. Photo: AAP

Mr Tsipras returned from Brussels on Monday after striking a deal with his eurozone counterparts.

He defended the deal saying although it had been “a bad night for Europe” and “imposed” on Greece, the agreement saved it from exiting the euro and must be implemented.

Protesters marched against austerity in central Athens in the morning, holding banners reading “Cancel the bailout!” and “No to the policies of the EU, the ECB and the IMF”.

“After five years of salary cuts and harsh measures the Europeans still want more,” said Stavros Koutsioubelis, a spokesman for the ADEDY public sector union, urging MPs to reject the deal.

Unions, but also MPs in Mr Tsipras’ leftist Syriza party, chafe at a raft of tax hikes and pension reforms that must be passed in the vote if bailout talks with international lenders are to start.