Greek Prime Minister Alexis Tsipras told Angela Merkel it would be "impossible" for Greece to make payments on its short-term debt obligations if it does not receive emergency financial assistance from the European Union.
Tsipras sent Merkel a letter, dated 15 March, warning that the government would be forced to choose between paying off its loans or fulfilling its social spending commitments, the Financial Times reported.
The Greek PM complained the European Central Bank has halted Athens' ability to issue short-term debt and also blamed the Eurogroup for refusing to release bailout finance until the new government sent a comprehensive list of economic reforms, the FT reported.
"It ought to be clear that the ECB's special restrictions when combined with disbursement delays would make it impossible for any government to service its debt," Tsipras wrote.
He warned that if Greece paid its short-term debts it would cause a "sharp deterioration in the already depressed Greek social economy – a prospect that I will not countenance."
Tsipras is due to meet with Merkel on Monday (23 March) as Athens seeks to solve its cash-flow crisis and avert bankruptcy.
Merkel said on Friday that Athens would not receive additional financial support until its reform programme had been submitted and approved by creditors, the largest of which is Germany.
It is not clear whether Tsipras will bring a list of reforms to the Monday meeting, which is thought to be an opportunity for the leaders to repair their working relationship, rather than a bargaining session.