Israel has denied that shots were fired during an incident in which Israeli fighter jets were alleged to have buzzed a German naval vessel.
Germany is taking part in a UN peacekeeping mission
Israel confirmed that an incident took place but denied reports that the Israeli jets fired two shots.
The two countries' defence ministers have reportedly discussed the incident.
Germany sent navy but not ground forces to join the Lebanese peacekeeping mission because it wanted to avoid any chance of a clash with Israeli forces.
Sensitivities remain over Germany's Nazi past.
The German newspaper Der Tagesspiegel revealed that an incident took place on Tuesday this week, quoting a German junior defence minister as saying two Israeli F-16 fighters had flown low over the German ship, firing twice.
The German ship - an unarmed reconnaissance vessel - adopted defensive measures, the report said.
"There was no such incident," an Israeli military spokeswoman told Reuters.
She said Israeli jets were scrambled when a helicopter took off from a German vessel close to Israeli waters without identifying itself.
The pilots realised what had happened and returned to base without incident, she said.
But in Germany opposition lawmakers demanded further explanation.
Birgit Homburger, of the opposition Free Democrats, which opposed Germany's deployment to the region, asked the government to say what would happen if Israeli jets overflew German ships again.
Germany's navy is part of the UN peacekeeping force deployed to the Israeli-Lebanese border following the conflict between Israel and Hezbollah earlier this year.