During her visit to Ukraine, Development Minister Svenja Schulze asked Russian President Vladimir Putin to allow grain deliveries via the Ukrainian ports.
"Putin is to blame for the fact that there are now possible famines in many countries," said Schulze on Friday in the Kiev suburb of Borodyanka.
Schulze dismissed Russian accusations that Western sanctions were provoking a global hunger crisis.
Food is excluded from the sanctions, emphasized the minister, who was the second German government member to travel to Ukraine.
"But what Putin is actually doing is that he is bombing the ports and thereby preventing food from being exported from Ukraine at all."
That has to stop, Schulze demanded.
Russia had called the partial lifting of Western sanctions a condition for solving the global food crisis.
At the same time, Moscow rejected accusations of blocking Ukrainian ports.
These are inaccessible due to sea mines laid by Ukraine itself.
The Russian Ministry of Defense published time windows and corridors for the possible exit of foreign ships from Ukrainian waters for the first time on Thursday.
However, Kyiv is responsible for the security of the port exit.