Besides facilitating an exit for the US from Iraq, the proposal will seek an international presence in the country instead.
"The idea is to see if Spain, France and Germany can help the United States find an exit from Iraq and devise a formula for an international presence there that would not be perceived as an occupation by most of the population," a Spanish government source said on Tuesday.
The initiative comes in the wake of Spain's new Prime Minister Jose Luis Rodriguez Zapatero's decision to withdraw Spanish troops deployed in Iraq.
Zapatero is to make the proposal during talks with German Chancellor Gerhard Schroeder in Berlin on Wednesday and with French President Jacques Chirac on Thursday.
Asked whether Spain would be prepared to send troops back to Iraq under such a formula, the source said it was too soon to say.
Any joint Spanish-French-German proposal would probably unfold in the UN Security Council though the source said the form it might take had not been decided.
Spanish Foreign Minister Miguel Moratinos has mentioned the possibility of sending Arab forces into Iraq, and of a future international presence that would not include soldiers from countries which have been part of the US-led war.
France and Germany were the leading opponents to military intervention in Iraq.
Under Zapatero's predecessor, Jose Maria Aznar, Spain was a staunch supporter of Iraq's invasion. But the policy was reversed immediately after Zapatero assumed office earlier this month.