Speaking after hosting his Qatari counterpart on Friday, German Foreign Minister Sigmar Gabriel called for the "sea and air blockades" to be lifted.
The Qataris deny accusations that they support Islamist extremists.
Ever since the dispute between Qatar and its neighbours erupted, Germany has pushed for a diplomatic solution.
Mr Gabriel met Saudi Foreign Minister Adil al-Ahmad al-Jubayr two days ago, and said all parties were seeking "to avoid further escalation".
Then on Friday, Mr Gabriel spoke to Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman al-Thani in the northern German town of Wolfenbuettel.
"We are convinced that now is the hour of diplomacy and we must talk to each other; along with our American colleagues but above all our colleagues in the region, we must try to find solutions, especially lifting the sea and air blockades," he told reporters afterwards.
'No surrender'Also on Friday Saudi Arabia and its three allies issued a list of 49 people - including Muslim Brotherhood spiritual leader Yusuf al-Qaradawi - and 12 Qatar-backed charities and groups accused of links with militants.
Qatar responded by saying that the list reinforced "baseless allegations".
He also called the moves against Qatar "violations of international law and international humanitarian law".
He added: "We are not ready to surrender, and will never be ready to surrender, the independence of our foreign policy."
Qatar is heavily dependent on food imports and the crisis has led to stockpiling and shortages.
Saudi Arabia has said Qatar needs to cut ties with the Palestinian Islamist group Hamas in the Gaza Strip, and the Muslim Brotherhood in Egypt, if it wanted to end its isolation.
Qatar is home to the biggest American air base in the region.
US President Donald Trump this week urged Gulf unity in a call to Saudi Arabia's King Salman.
However, he had earlier claimed credit for the pressure placed on Qatar saying his recent visit to Saudi Arabia was "already paying off".
Read more: http://www.bbc.com/news/world-middle-east-40219622