Merkel, in her harshest comments to date, decried what she called "the monstrosity there in the Saudi consulate in Turkey" during a campaign rally in the town of Ortenberg before a regional election in the state of Hesse on Sunday.

"It must be cleared up. As long as it's not cleared up, there will be no arms exports to Saudi Arabia. I assure you of that very decidedly," Merkel said.

Riyadh has given multiple and conflicting accounts on what led to Khashoggi's death on October 2. On Sunday, Foreign Minister Adel al-Jubeir called the killing a "huge and grave mistake" but sought to shield Saudi Arabia's powerful crown prince.

Merkel first called for a stop to arms exports on Sunday, raising questions about whether that would also affect deliveries that had previously been approved. Her spokesman told reporters earlier on Monday the question was being reviewed.

Norbert Roettgen, a member of Merkel's conservatives and head of the parliamentary foreign affairs committee, said it was clear that all deliveries of weapons to Saudi Arabia should be halted, even those approved before Khashoggi's death.

"Even those deals that were already approved cannot happen now, as long as the case has not been resolved, and as long as there have been no substantial consequences in Riyadh," Roettgen told broadcaster ZDF. "We would completely lose our credibility."

Economy Minister Peter Altmaier earlier had called on other European Union member states to follow its example in stopping arms exports to Saudi Arabia to increase pressure on Riyadh over the Khashoggi case.

Riyadh's explanations so far had not been satisfactory, Altmaier told broadcaster ZDF, adding, "The government is in agreement that we will not approve further arms exports for the moment because we want to know what happened."

So far this year Berlin had approved weapons exports worth more than 400 million euros ($A651 million) to Saudi Arabia, making it the second-biggest recipient of German arms after Algeria.

Australian Associated Press