Despite expectations the European Central Bank will flesh out details of its proposed bond buying programme at its policy meeting on Thursday, demand for lower-risk bonds has been strong this week at Belgian and Austrian auctions, while Bunds have been trading in a tight range.
"Bunds might come under a bit of pressure ahead of the auction but at the end of the day we're waiting for tomorrow," a trader said.
"The market seems to be expecting a massive solution, the swing in sentiment does seem to have gone too far that way."
German Bund futures were 10 ticks higher at 143.60.
Germany will sell 5 billion euros of the new September 2022 paper, which carries a record-low coupon of 1.5 percent.
However, analysts had mixed views on how the auction would go, although noting the bond was trading at a fair value, or even slightly cheaply, in the grey market.
"This week's heavy long-end supply from core-issuers as well as the looming ECB meeting could weigh on the auction," Commerzbank strategists said in a note.
"Against this backdrop, the take-down of the new Bund will thus largely be a function of the prevailing risk-sentiment in the run-up to the auction."
The launch of Germany's last 10-year benchmark in April failed to attract enough bids to cover the amount on offer - the only time that has happened this year.
The Netherlands will also sell a three-year dollar denominated bond, coming to market at short notice to take advantage of the good demand for core bonds.