Federal prosecutors are already investigating a secret army conversation on the Ukraine war that was wiretapped and ended up on Russian social media in March.

The latest security flaw that Zeit Online reported on again concerned the online video-conference tool Webex, a popular public platform for audio and video meetings, with additional security buffers built in.

Zeit Online said it had been able to access Germany army meetings by using simple search terms on the platform.

"More than 6,000 meetings could be found online," some of which were meant to be classified, it wrote.

Sensitive issue covered included the long-range Taurus missiles that Ukraine has been calling for, and the issue of online warfare.

Online meeting rooms attributed to 248,000 German soldiers were easy to detect thanks to weak online design that lacked even password protection, Zeit Online added. That allowed its reporters to find the online meeting room of air force chief Ingo Gerhartz.

His name came up during reports of the earlier leak in March, when a recording of the talks between four high-ranking air force officers was posted on Telegram by the head of Russia's state-backed RT channel. He was one of the four officers recorded.

Zeit Online said that the army only became aware of the security flaws after they approached them for comment. The security issue was first identified by Netzbegruenung, a group of cyber-activists, it reported.

An army spokesman confirmed to AFP that there was a flaw in the army's Webex sites but that once it had been drawn to their attention they had corrected it within 24 hours.

"It was not possible to participate in the videoconferences without the knowledge of the participants or without authorisation," he added. "No confidential content could therefore leave the conferences."

Zeit Online said the Webex sites of Chancellor Olaf Scholz as well as key government ministers had the same flaws and that they had been able to connect to Scholz's site on Saturday.