Since Moscow had shown scant interest in determining the exact circumstances of the airliner's destruction, Chancellor Angela Merkel now wanted "swift" economic sanctions imposed by the EU against Russia, spokesman Georg Streiter said.
Nor had Russia done enough to rein in armed separatist forces in eastern Ukraine which were partly being led by veteran employees of the Russian intelligence services, Reuters news agency quoted the spokesman as saying.
"Russia has so far promised much and delivered nothing. Enough's enough," a spokeswoman for the German Foreign Office added.
On Wednesday, two Ukrainian fighter jets were shot down by pro-Russian separatists in eastern Ukraine.
If Merkel is successful in her quest for a harder line on Russia, she will have the support of the majority of Germans, a new poll indicates.
The survey conducted by the YouGov public opinion centre found that 53 percent of German respondents wanted tough economic measures imposed on Russia, which Britain and the United States accuse of supplying the missile used to shoot down the aircraft last Thursday. All 298 people on board died.
Only 26 percent opposed sanctions in the poll, which was conducted on Monday and Tuesday.
The same number favoured freezing Russian bank accounts in the West, with 30 percent of the 1,070 respondents against.
However, few people want to see any military involvement in the escalating crisis in Ukraine, with 64 percent opposing military aid to the government in Kiev and only 18 percent for.
Similar numbers favoured and opposed severing diplomatic ties with Russia (22 percent in favour to 62 percent against).
Opinion was more evenly split over the issue of providing financial assistance to Kiev, with 40 percent for and 36 percent against.
The debate over sanctions intensified rapidly after the Malaysia Airlines passenger plane was brought down near the border with Russia.
But a meeting of the European Union's 28 foreign ministers in Brussels on Tuesday failed to reach agreement on economic reprisals against Russia for its role in fomenting violence in Ukraine.
Ministers agreed only to draw up a new and broader list of targets for sanctions that included Russian individuals and entities. However, many EU members are reluctant to hit Russia hard as it is a key provider of oil and gas to European countries.
World Cup losers?
Meanwhile, a number of German politicians are calling for the 2018 World Cup to be taken away from Russia as host nation and relocated to another country.
"A country that can't even guarantee the [safe] passage of aircraft should not organize the World Cup," the deputy head of the CDU/CSU centre-right coalition, Michael Fuchs, told the Hannoversche Allgemeine Zeitung.
The choice of Russia to hold the championship was "inappropriate," said Fuchs, who suggested that the 2014 winners Germany should step in as host.
"You cannot hold the World Cup in a country that violates international law to annex part of another country," added Green Party politician Volker Beck.
"Awarding the World Cup to Russia was already questionable before the Ukraine crisis because the Kremlin has been continually restricting citizens' rights for years," added Marieluise Beck, chairperson of the Greens faction in the German Parliament.
Russian President Vladimir Putin was "not a worthy host," she said.
However, the government spokesman Streiter said: "We have more urgent problems than this," noting that the German government had no say in that decision.
Fifa, which oversees the World Cup, has not let itself be drawn into the debate.
The international football federation is currently investigating alleged corruption in the initial awarding of the championship to Russia four years ago. Results of the probe are due to be presented in September.
Russian Sports Minister Vitaly Mutko responded to discussion of withdrawal of the World Cup after the destruction of the airliner by saying: "I can see no connection. These are different things. This will not affect the World Cup."
Mutko is also a senior World Cup organization official and member of Fifa's executive committee.