The German parliament is due to back a rare cross-party motion later on Thursday demanding that Israel lift its blockade of the Gaza Strip immediately, in an unusual demonstration of unity against Israeli policy.

Open gallery view German Chancellor Angela Merkel Credit: AP

The motion by lawmakers in Chancellor Angela Merkel's conservatives, her coalition partners the Free Democrats (FDP), and the main center-left opposition parties follows calls from Germany that Hamas, which controls Gaza, should be brought into the negotiating process.

Following the Nazi genocide of European Jews in World War II, Germany's main political parties have staunchly supported Israel. They have also strongly criticized Hamas, an Islamist group which refuses to recognize Israel.

However, the 2008 Israeli invasion and blockade of Gaza sparked criticism of Israel, which considers Hamas a terrorist organization and refuses to negotiate with it.

"The living conditions of the civilian population of Gaza must be urgently improved," said the German motion, adding that the blockade - which the government has already said should be ended - was counterproductive and did not help to make Israel safer.

In response to Western criticism, Israel has eased the land blockade of Gaza where 1.5 million Palestinians live, allowing most civilian goods through, while continuing to enforce a naval embargo of the coastal territory.

The German parliamentary initiative also urges Merkel's government to press for a resumption of peace talks in the region.

"The motion will be adopted. There's no doubt," Rainer Stinner, foreign policy spokesman for the FDP, told Reuters.

In parliament, only the Left Party did not help to draft the motion, but the far-left grouping would also support it, said its foreign policy spokesman Wolfgang Gehrcke. "This marks a profound shift in policy towards Israel in Germany, in my view," he said.

This week, the opposition center-left Social Democrats (SPD) said dialogue with Hamas now looked inevitable due to support for them in Gaza, and the FDP's Stinner agreed.

"If you want to achieve anything in the Gaza Strip, you can't get around making contact with Hamas," he said.

Merkel's Christian Democrats (CDU) were more guarded about the prospect of dealing with Hamas, saying the organization had failed to renounce violence unequivocally or recognize Israel.

However, they did not rule out talks categorically.

Ruprecht Polenz, a senior CDU lawmaker and head of the Bundestag's foreign policy committee, said Hamas hoped to exploit talks to obtain international recognition.

"It doesn't necessarily follow from this that you shouldn't speak to Hamas at all," he said. "But it follows you shouldn't talk to them in a way which raises their international standing - unless they show a substantial change in their position."