Hammond made the call in Paris after a major conference on Iraq.
"It was always unlikely that Iran would become a fully fledged member of the coalition, but I think we should continue to hope that Iran will align itself broadly with the direction that the coalition is going," AFP quoted Hammond as saying.
He also said he hoped Iran would be "cooperative with the plans that the coalition is putting in place, if not actively a part of the coalition."
Iran, which was not invited to the conference, has said that it would not engage in military cooperation with the US in Iraq.
The 30 states and organizations took part in the Paris conference agreed to support the Iraqi government "by any means necessary" to fight the extremists, including "appropriate military assistance".
Hammond said Britain had not so far "made any decision on whether or not it is going to engage in air strikes at this stage.
The British minister said air strikes in Syria would be a far more complicated matter than in Iraq and of a far bigger magnitude for "all sorts of reasons, military, legal and technical, but we haven't ruled it out."