The Forsa agency's poll for Stern magazine put support for Merkel's Union bloc at 42 percent, a point higher than two weeks earlier. That's the highest level the agency has measured since Merkel became chancellor in November 2005.
Merkel has been helped by a robust economy and her handling of Europe's debt crisis but the weakness of her coalition partners, the pro-market Free Democrats, is a complication as she seeks a third term. The party has taken much of the blame for frequent coalition infighting and has been bickering over the future of its embattled leader, Vice Chancellor Philipp Roesler.
The survey showed a parliamentary majority neither for the current center-right coalition nor for its center-left rivals.
It put support for the main opposition Social Democrats at 25 percent, a two-point slip, with their allies, the Greens, gaining two points to 15 percent. The survey was conducted after Merkel's Social Democratic challenger, Peer Steinbrueck, drew widespread criticism for saying the chancellor earns too little and Merkel has an advantage because she's a woman.
That added to earlier controversy over Steinbrueck's high earnings from giving lectures while he served as a backbench lawmaker. Steinbrueck has long had a reputation for plain speaking, but his recent comments haven't helped a party which makes narrowing the gap between Germany's haves and have-nots a key issue.
Germany's national election is due in September. The opposition hopes for a boost from a Jan. 20 election in the northern Lower Saxony region, where it aims to oust Merkel's coalition from the state government.