Markets | Sat May 23, 2015 11:06am EDT

BERLIN

German Finance Minister Wolfgang Schaeuble has said there is no need to consider disbursing more aid to Greece because Athens has already promised reforms and must tackle the problem itself.

In a radio interview to be aired on Sunday, Schaeuble said: "Greece vowed to fulfill the program on Feb. 20 and as a result there's no need to talk about alternatives."

"There's no getting around that it's an issue for the government in Athens," Schaeuble told Deutschlandfunk radio, according to excerpts of the interview released on Saturday.

In the latest warning that Greece is teetering on the brink of default, a senior Greek ruling party lawmaker said on Wednesday that it could not make a payment due to the IMF on June 5 unless foreign lenders disbursed more.

In an interview with Reuters last week, Schaeuble said such a payment would contravene an agreement between the Eurogroup of euro zone finance ministers and Greece on Feb. 20, when Athens was granted a four-month extension of its rescue package in return for promising economic reforms.

In the Deutschlandfunk interview, Schaeuble evaded a question about whether he thought Greece was closer to being rescued or defaulting. He said, however, Greece "has a lot of work" ahead of it.

Schaeuble also said that the Group of Seven (G7) leading industrial nations, whose finance ministers will be meeting in Dresden next week, cannot solve Greece's problem.

Prime Minister Alexis Tsipras's leftist government says it hopes to reach a cash-for-reforms deal in days, although European Union and IMF lenders are more pessimistic and say talks are moving too slowly for that.

Greek officials now point to a race against the clock to clinch a deal before payments totaling about 1.5 billion euros ($1.7 billion) to the IMF come due next month, starting with a 300 million euro payment on June 5.

Schaeuble also told Reuters that the Greek government's optimism about clinching a cash-for-reforms deal with its lenders within days is not backed up by the negotiations, and he could not rule out Greece becoming insolvent.