And he praised US President Barack Obama as a man of his word for having honoured promises over a pull-out from Iraq and shutting down the detention centre at Guantanamo Bay, in comments to the Italian daily La Repubblica.
"I am ready to serve as a mediator with Iran," he told the newspaper.
"If we are talking Iranian influence on Iraq, you have to make a distinction: the influence is not negative if it is founded on mutual respect," he said.
"It is another thing to interfere," he added.
"If however we are talking facilitating diaologue with Iran, you have to submit a concrete proposal to this government.
"Up until now I have only received an invitation to play a role. I am willing to, but that is not enough: what is lacking is a plan, precise rules and mechanisms to submit to Tehran," he said.
Western powers such as the United States and the European Union have clashed with Iran over a number of issues including its role in neighbouring Iraq and its nuclear programme.
The West wants proper monitoring to ensure that Iran, which insists its bid to develop nuclear energy is exclusively for civilian use, does not use it to develop a military nuclear capacity.
Assad insisted that dialogue was essential to clear up these disputes.
"Any attempt to contain a country ends up by strengthening it," he argued.
"Whether you like it or not, Iran is an important country."
He described the early moves by US President Barack Obama as encouraging.
"With the withdrawal from Iraq, the willingness for peace, the closure of Guantanamo, he has shown himself to be a man of his word," he said.
"But it is still to early to say if this is a historic turning point.
"The only certainty is that after the 'night' that was the administration of (former US president George W.) Bush, hope has returned."
Obama would have to restore the credibility of the United States, he added.
