Greece's new leaders will be unable to attend this week's EU summit on the euro crisis or host the "troika" team of creditors in Athens because two senior figures in the incoming administration are ill.

Days after a new conservative-led coalition was installed, doctors said the new prime minister, Antonis Samaras, would be unable to attend the Brussels summit. International auditors then said they had been forced to postpone a visit to assess Greece's financial progress.

The inspection tour by monitors from the EU, European Central Bank and International Monetary Fund, the first since March, had been seen as key to releasing rescue funds for the cash-strapped Greece. But officials said on Sunday the hospitalisation of Samaras and his finance minister, Vassilis Rapanos, had meant it would be delayed until both were back at work.

In the case of Samaras, 61, who underwent an eye operation on Saturday, that is not likely for at least a week. On Sunday the prime minister's physician, Panaghiotis Theodosiadis said he had "staunchly forbidden" Samaras from any travel following "difficult surgery" for a detached retina. After his release from an Athens clinic on Monday, the conservative leader would have to stay at home for at least a week to "fully recover" the doctor told reporters gathered at the hospital.

Rapanos, 65, was under orders to rest after fainting on Friday. He was taken to hospital, where doctors revealed he was suffering from intense abdominal pain, nausea and dizziness, and is expected to stay until Tuesday, but it is unclear if he will be able to travel after that, said the daily Vima on Sunday.

Rapanos, a respected economist who was imprisoned during Greece's 1967-1974 military dictatorship after he was caught targeting banks with bombs, has long battled health problems. He had still not been sworn in when he collapsed on Friday.

Greece, which will now be represented by a four-strong team headed by the foreign minister, Dimitris Avramopoulos, had announced that it would launch efforts to ease the punishing terms of its latest €130bn (£104bn) international rescue package at the summit.

Athens is under pressure from foreign lenders to restart a reform programme delayed by uncertainty during its elections. But Greeks have become increasingly radicalised after five years of recession and austerity that have left many facing poverty and unemployment.

At the weekend, the new government said it would seek to freeze public sector layoffs, reverse cuts in pensions, reduce taxes and extend help to the rising numbers of poor people. Athens has pledged to try to extend its financial support programme by two years to meet deficit reduction targets – goals bound to put it on a collision course with EU countries propping up the economy.