Greek Finance Minister Yanis Varoufakis said Sunday German Chancellor Angela Merkel "holds the key" to resolving the Greek crisis, while stressing Athens remains open to further talks with international creditors.

Athens was ready for "new proposals by the institutions" -- the EU, European Central Bank and International Monetary Fund -- ahead of a Greek referendum on bailout terms set for next weekend, he told Germany's Bild newspaper.

"As far as we are concerned, we remain ready to negotiate in the time in which the people must reach their assessment," he said in pre-released excerpts of an article from Monday's edition.