German Chancellor Olaf Scholz on Saturday promised a full investigation after what appeared to be a recording of confidential army talks on the Ukraine war was posted on Russian social media, in a potentially huge embarrassment for Berlin.

The head of Russia's state-backed RT channel, Margarita Simonyan, on Friday posted the 38-minute audio recording of what she claimed were German army officers on February 19 discussing potential strikes on Crimea.

"What is being reported is a very serious matter and that is why it is now being investigated very carefully, very intensively and very quickly," Scholz said on a visit to Rome.

In the recording, discussions can be heard on the possible use by Ukrainian forces of German-made Taurus missiles and their potential impact.

Topics include aiming the missiles at targets such as a key bridge over the Kerch strait linking the Russian mainland to Crimea, which was annexed by Russia in 2014.

The discussions also cover the use of missiles provided to Kyiv by France and Britain.

A German defence ministry spokeswoman confimed to AFP that the ministry believes a conversation in the air force division was "intercepted".

"We are currently unable to say for certain whether changes were made to the recorded or transcribed version that is circulating on social media," the spokeswoman said.

Experts consulted by Der Spiegel magazine said they believed the recording was authentic.

Kyiv has long been clamouring for Germany to provide it with Taurus missiles, which can reach targets up to 500 kilometres away.

Scholz has so far refused to send the missiles, fearing that it would lead to an escalation of the conflict.

"If this story turns out to be true, it would be a highly problematic event," Green party politician Konstantin von Notz told the RND broadcaster.

"The question arises as to whether this is a one-off incident or a structural safety problem," he added.

Speaking at a diplomatic forum in Turkey on Saturday, Russian Foreign Minister Sergei Lavrov said the recording indicates that Ukraine and its backers "do not want to change their course at all, and want to inflict a strategic defeat on Russia on the battlefield".

Foreign ministry spokeswoman Maria Zakharova demanded that Germany "promptly" provide explanations for the discussion.

"Attempts to avoid answering the questions will be regarded as an admission of guilt," she said.

"Our age-old rivals -- the Germans -- have again turned into our sworn enemies," former Russian president Dmitry Medvedev, now deputy head of the Security Council and the foreign ministry, wrote in a Telegram post. (AFP)