Guido Westerwelle told German broadcaster ARD that Russia's justification for vetoing the resolution was unconvincing and a sign of that there was "a great deal of political tactics" at work.
The resolution was approved by all members of the 15-country Security Council except Russia and China, who are two of the body's permanent members.
In a statement, UN Secretary General Ban Ki-moon called the result "a great disappointment to the people of Syria and the Middle East, and to all supporters of democracy and human rights."
UN Human rights officials now say more than 5,000 people have been killed amid the unrest in the country.
The Security Council draft resolution, which was submitted by Morocco, called on members to support an Arab League plan that demands an immediate end to the violence in Syria, as well as national dialogue.
Russia's ambassador to the United Nations, Vitaly Churkin, said Russia "regretted the outcome," saying Moscow had wanted to find a compromise.
"But these attempts were undermined by countries that wanted too much, even a regime change," he said.
The German foreign minister called on his Russian counterpart, Sergei Lavrov, to send a clear message to Syrian President Bashar al-Assad during his upcoming trip to Damascus, which is scheduled for Tuesday.
Westerwelle told ARD that Germany would not be deterred from helping the Syrian people.