* German parties urge referendums on major EU decisions
* Greek yields bounce off post-restructuring lows
* Bunds track weaker U.S. Treasuries after strong jobs data
By Marius Zaharia
LONDON, Nov 12 (Reuters) - Greek bond yields jumped on Tuesday on concerns that a proposal for German parties to hold nationwide referendums for major European decisions may complicate Athens's efforts to overcome its debt crisis.
Such decisions include Germany committing money at EU level and powers transferred from Berlin to Brussels and could affect Berlin's ability to act swiftly in a crisis, making aid-reliant members like Greece more vulnerable.
"Anything which would slow the aid mechanism would be enough to ... trigger some repricing of these bonds," said Commerzbank rate strategist David Schnautz.
Greek 10-year bond yields rose 43 basis points to 8.58 percent, having fallen as low as 7.94 percent at the start of November - their lowest since Greece's debt restructuring in March 2012. Other Greek bond yields also rose.
The proposal looked likely to be quashed by Chancellor Angela Merkel, but traders said investors still sold Greek bonds on the back of it, if only to book profits on the recent rally.
Unless the proposal looks more likely to be realised, it is unlikely to lead to a major sell-off, traders said.
"I don't think something like this will pass. If this passes, we will have problems everywhere, not just in Greece," one fixed income trader in Athens said.
Yields of other low-rated euro zone bonds also rose, most notably Portugal's, which partly reversed a fall in the wake of a Moody's revision of the country's rating outlook to stable from negative.
Ten-year Portuguese yields rose 8 bps to 5.96 percent.
"From the market behaviour point of view, trying to get things through (with referendums) is unsettling. You can open a can of worms which can cause mayhem," said Alan McQuaid, chief economist at Merrion Stockbrokers.
MIND THE TAPER
German Bund futures hit three-week lows on Tuesday, tracking weaker U.S. Treasuries, on bets the Federal Reserve could trim its bond purchases earlier than previously expected.
This followed forecast-beating U.S. jobs data on Friday which wiped away Bund gains triggered by the European Central Bank's surprise rate cut last week.
Speeches from Fed officials Dennis Lockhart and Narayana Kocherlakota will be trawled for hints on when the central bank might start rolling back its monetary stimulus.
The Bund future closed 31 ticks lower at 140.70, having earlier hit 140.53, its lowest since Oct. 23.
U.S. 10-year yields were up 2.4 bps at 2.77 percent resuming their rise after a Veterans' Day holiday on Monday.
A Reuters poll on Friday after the jobs report showed economists at several primary dealers thought the Fed would cut its bond purchases as soon as January. Just two weeks ago, a similar poll found the majority backing the central bank to hold off until next March.
"People may have the robust payrolls situation in the U.S. in their minds. Nobody wants to rule out tapering in December, said Ralf Umlauf, head of floor research at Helaba Landesbank Hessen-Thueringen.