Greek ministers have launched a concerted effort to persuade European officials to release more bailout money as the government runs out of cash.
Finance Minister Yanis Varoufakis was meeting his French counterpart before heading for Brussels, while colleagues headed for the European Central Bank.
The EU and IMF will not release €7.2bn (£5.3bn; $8bn) until they are satisfied with Greek plans for economic reform.
The EU has now slashed its 2015 growth forecast for Greece from 2.5% to 0.5%.
The Greek government is desperate to reach a deal with its international creditors before a scheduled €1bn debt interest repayment to the IMF on 12 May, but the two sides have yet to agree on labour reforms and pensions.
Prime Minister Alexis Tsipras spoke to German Chancellor Angela Merkel over the phone on Monday night, but a Greek official said only that they had exchanged views on the relevant issues.
As his government pushed for a compromise, EU Economic Affairs Commissioner Pierre Moscovici said that “in light of the persistent uncertainty”, revising the forecast for Greece’s growth had been unavoidable.