Adding to the uncertainty, German lawmakers secured a full parliamentary vote on euro zone crisis measures negotiated by Chancellor Angela Merkel and her peers, a move which risked delaying Europe's response to its two-year debt problems.

Merkel will not be able to agree to changes to the 440 billion euro European Financial Stability Facility (EFSF) without approval of parliament.

"You'd imagine things aren't going to get sorted out in a few minutes...We are sticking to our view that the summit will under deliver when (the plan) is finally announced," a trader said.

The Bund future was last 16 ticks up at 134.93 compared with 134.77 at Monday's settlement. Cash 10-year Bund yields were 3.6 basis points down at 2.08 percent .

Traders and strategists said the expected the market to remain volatile going into Wednesday's summit, with thin volumes adding to the sharp market moves.

"I don't see any reason why we can't go up and down 20 basis points in yields on very little news at the moment," the same trader said.