Greek Finance Minister Yanis Varoufakis will meet IMF chief Christine Lagarde in Washington on Sunday ahead of the country's April 9 deadline for its next payment to the fund.  
Varoufakis and Lagarde will have informal discussions on the Greek government's reform programme, according to the IMF and a Greek Ministry of Finance statement on Saturday.
Another government source told AFP that Varoufakis "will also meet with United States Treasury officials" on Monday, including Under Secretary for International Affairs Nathan Sheets.
The meetings come amid speculation that Athens might fail to meet the 460-million-euro ($501-million) IMF instalment if forced to choose between the IMF and paying government workers.
Greece has not received the funds remaining in its 240-billion-euro EU-IMF rescue package as Brussels has demanded to first approve Greece's revised reform plan.
But junior finance minister Dimitris Mardas said Saturday that the state does have the money needed for the IMF payment.
"The payment to the IMF will take place on April 9. There is money for the payment of salaries, pensions and whatever else is needed in the next week," he told Mega TV.
The IMF meanwhile denied a report in the German magazine Spiegel that it had withdrawn its staff temporarily in protest at the Greek government's slowness in implementing reforms.
Athens is betting much on the next week's Euro Working Group for some relief from its creditors.
Eurozone deputy finance ministers will meet on April 8 and 9 in an attempt to reach an agreement on the list of Greek reforms needed to unlock the last tranche of the bailout package.