The proposal is for a beefed-up version of Europe's temporary bailout for Greek banks to ensure that they have adequate collateral with the European Central Bank.
It would increase the effective lending capacity of the emergency financial stability facility to à440-billion (R4.26-trillion) and enable member states to double the guarantees they give the fund.
Germany's guarantees would climb to à246-billion from à123-billion, according to the report.
The plan to lend to Greek banks through the facility would complement a second bailout for Greece of between à90-billion and à120-billion, Der Spiegel reported.
Schaeuble's latest plan is an attempt to resolve a dispute with the ECB, which, along with other eurozone leaders, rejected a plan to swap existing Greek debt for new bonds with longer maturities.
The ECB has repeatedly warned that such a move would amount to a default and disqualify Greek bonds as collateral for the central bank's liquidity-providing operations.
Without ECB liquidity, Greek banks would be cut off from funding, touching off a banking crisis.
"Schaeuble would like to eliminate an argument by the ECB which has, until now, stood in the way of a write-off by private creditors," Der Spiegel said.
German Chancellor Angela Merkel and French President Nicolas Sarkozy agreed on Friday to a plan by which private bondholders could volunteer to buy new government bonds to replace those that matured.