Proposed reforms win conditional approval in Brussels for extension of rescue package that new Greek government has repeatedly pledged to scrap

Greece’s new leftwing government faces months of fraught negotiations with its creditors over how to ease its unsustainable debt levels and austerity programmes after securing - but only conditionally - a eurozone lifeline on Tuesday that wins it time until the end of June.

Alexis Tsipras, the Greek prime minister and leader of the Syriza movement, had to bow to German-led pressure to stick to the broad terms of its €240bn (£176bn) bailout in order to obtain a four-month extension to the rescue he repeatedly pledged to scrap.

Late on Monday the new finance minister, Yanis Varoufakis, sent a six-page list of proposed economic reforms to Brussels which held to some of Tsipras’s election campaign pledges, but largely diluted or abandoned them to win the support of the other 18 governments in the eurozone, and of the troika of bailout overseers from the European commission, the European Central Bank (ECB) and the International Monetary Fund (IMF).

Despite Tsipras’s assertions, for domestic consumption, that the hated troika is dead and that the bailout programme has been ditched, both remain very much in play, with the troika grudgingly blessing Tuesday’s proposals from Athens and mandated to deliver a more detailed verdict by the end of April.

“Greeks have lots of heavy-lifting to do until end-April. We all want to see numbers now,” tweeted the Slovak finance minister, Peter Kazimir.

The European commission was quick to support the Greek formula, but the ECB and the IMF were much more ambivalent while agreeing to the bailout extension.

Christine Lagarde, the head of the IMF, and Mario Draghi, the ECB president voiced strong reservations about the Tsipras proposals in letters to the Dutch finance minister and head of the eurogroup, Jeroen Dijsselbloem .

Lagarde said the Greek menu of policies was not sufficiently specific, and did not go far enough, singling out VAT, pension and labour market reforms and privatisation as issues.

“We consider such undertakings critical,” she wrote. “In quite a few areas, including perhaps the most important ones, the [Greek] letter is not conveying clear assurances.”

The ECB complained that “the commitments outlined by the [Greek] authorities differ from existing programme commitments … We will have to assess whether measures that are not accepted by the authorities are replaced with measures of equal or better quality.”

The objections from the ECB and IMF mean that the jury is still out on Tsipras’ plans, but that he will be given the benefit of the doubt for now.

With €7.2bn remaining to be tapped from the bailout funds, another €10bn reserved by the Europeans for recapitalising Greek banks and Athens having to make big debt repayments by next month, it is not clear whether any money will be disbursed before the troika verdict at the end of April. In the meantime, Tsipras is also under pressure to make start negotiations on a third rescue programme to take effect in July, when even bigger debt repayments are due.

Despite the European reservations, the Greek letter entailed a climbdown on earlier Tsipras pledges. He had promised to raise pensions and the minimum wage and backpedal privatisation, while also spending money on the “humanitarian needs”of the poorest.

Monday evening’s letter said the humanitarian aid would be fiscally neutral, not affecting the budget, that aid to the poor would be “non-pecuniary”, for example by issuing food stamps. It said that raising minimum wages would be delayed, there would be a clampdown on early retirement and completed privatisations would not be reversed.

Announcing plans to slash civil service funding, Varoufakis revealed that non-salary and non-pension expenditure in the public sector amounted to 56% of the total. He described this as “astounding”.

While Tsipras appeared to have scraped through his first test with the creditors, he may now run into trouble with his staunchly anti-austerity backbenchers barely a month after his election triumph. The prime minister made major concessions to the creditors over two days of intense negotiations with Brussels before presenting the proposals. But he can also boast that the policy mix unveiled is that of his government and no longer a script dictated by the troika, a major change in the bailout terms.

Tspiras declared at the weekend that the days of the troika and the bailout were over, but the German government, the IMF and the ECB emphasised the opposite on Tuesday, that the austerity terms agreed in return for the rescue funds had to be observed or at least matched in fiscal impact and that the troika remained the referee.

Several eurozone parliaments now have to vote to support the extension of the bailout, most notably the German bundestag on Friday. Without the extension, the eurozone rescue would lapse on Saturday, thrusting Greece into potential financial collapse.

Following a fortnight of standoffs and brinkmanship that resulted in Friday’s agreement between Athens and the eurozone and Tuesday’s amber light, all the signs are of further turbulence to come.