And 80 percent believed Greece is not acting in a reliable manner in its negotiations with eurozone partners, found the Politbarometer survey released by public broadcaster ZDF.
The proportion of respondents who think Greece should stay in the currency union has fallen to 40 percent from 52 percent two weeks ago, while 52 percent now believe it should leave, up from 41 percent.
Only 11 percent now think the left-wing government in Athens is behaving in a trustworthy way in talks with its EU partners.
And only 14 percent believe the Greek government will actually implement the austerity and reform measures it has committed to, while 82 percent doubt it.
Eighty percent believe Greece should get no more bailout funds if it fails to follow through on its pledges, according to the survey conducted by the Mannheim Research Group.
The poll also confirmed Chancellor Angela Merkel as the country's most popular politician, followed in second spot by Finance Minister Wolfgang Schaeuble.
Merkel and Schaeuble have championed tough austerity and reform demands in return for aid to Greece, making them hate figures for many in Greece as the country has chafed under cutbacks and high unemployment.
Politbarometer surveyed by telephone 1,266 randomly selected voting-age Germans between March 10 and 12.