Fresh from talks in Washington on Friday, he said he and Secretary of State Condoleezza Rice were asked to present ideas at a meeting of Nato foreign ministers in Lithuania on Wednesday.
It would be the 26-nation Western alliance's first involvement in the Arab-Israeli conflict, long regarded as outside its Euro-Atlantic area of operation.
But Nato has since expanded its reach to Afghanistan and has a small officer training mission in Iraq.
"Within Nato, Condoleezza Rice and I have been asked to open the debate and make proposals next Wednesday in Vilnius to debate Nato's role and define its contribution to the Middle East peace process," Motarinos told reporters.
"We have to find a common position of the Americans and the Europeans."
He gave no details, but diplomats said it was likely to involve training Palestinian officers and participating in a regional security dialogue. Any deployment of Nato forces was highly unlikely unless there is a final settlement to the Israeli-Palestinian conflict, he said.
European Union foreign ministers, including Moratinos, discussed on Saturday helping the peace process by training Palestinian police ahead of and after the planned Israeli withdrawal from the Gaza Strip later this year.
The EU already has a small police mission on the spot headed by a former chief of the British police in Northern Ireland.