"The penalty handed down to Raef Badawi is cruel, bad, unjust and totally disproportionate," Steinmeier said in comments to appear Sunday in the Bild am Sonntag weekly newspaper.
The German Foreign minister was lending his voice to a case which has already prompted worldwide outrage and criticism from the UN, US, the EU and others.
Rights group Amnesty International said Thursday that Saudi Arabia had decided to postpone Badawi's next session, for a second week on medical grounds.
The 30-year-old Saudi has been sentenced to 1,000 lashes for insulting Islam and is serving a 10-year jail term.
He received the first 50 lashes of his sentence outside a mosque in the Red Sea city of Jeddah on January 9.
"You can be sure that we will continue to do everything we can to promote a solution," to the Badawi case, Steinmeier said, adding that "the question of human rights plays a very important role in discussions between Berlin and Riyadh, even outside of this matter."
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Badawi's wife Ensaf Haidar, who has sought asylum with her children in Canada, told AFP by telephone that her husband's case has been referred to the supreme court, possibly paving the way for an appeal.
Badawi co-founded the now-banned Saudi Liberal Network along with women's rights campaigner Suad al-Shammari, who was also accused of insulting Islam and arrested last October.
The charges against Badawi were brought after his group criticised clerics and the kingdom's notorious religious police, who have been accused of a heavy-handed enforcement of sharia Islamic law.
Saudi Arabia is currently in mourning following the death of King Abdullah.
New Saudi King Salman has vowed to keep his conservative, oil-rich Muslim kingdom on a steady course and moved to cement his hold on power following the death of his half-brother King Abdullah.
Dignitaries and leaders from around the world were to arrive in Saudi Arabia Saturday to offer their condolences to King Salman following the death of his half-brother King Abdullah.
British Prime Minister David Cameron and French President Francois Hollande were among the first leaders expected while US Vice-President Joe Biden was due to visit in the coming days.
Germany will be represented by former president Christian Wulff.