Anglican vicar Rev Andrew Ashdown says the view of all warring parties need to be listened to.
Rev Andrew Ashdown traveled to Syria alongside Rev Michael Nazir-Ali, the former Bishop of Rochester and two cross bench peers, Baroness Cox and Lord Hylton, to discuss the plight of Christians in country since the outbreak of the civil war in 2011.
Their journey was heavily criticised by the vice-president of the All Party Parliamentary Group on Syria and Labour MP John Woodcock.
He said: "It is shocking to see British parliamentarians giving international pariah al-Assad a photo opportunity to distract from the brutal and ongoing slaughter he is perpetrating on Syrian families.
"The exact detail or process of the reconciliation in Syria may not be to the form that some here might think should be the case, but there's a process that's seeking to bring peace, there's a process that's working with different factions."
However Rev Andrew Ashdown said peace will not be achieved without taking into account the view of all sides.
"It's astonishing, it's nonsensical that we will not engage with people who are trying genuine ways of ending fighting, bringing reconciliation between different factions and rehabilitating different people with different views into their local communities," he said.
His comments come as the world welcomes a proposed peace deal which is scheduled to begin on Monday.
Russia and the US say a truce on Monday night will allow aid to be delivered.
Rev Andrew Ashdown told Premier their visit showed them how successful the reconciliation process could be.
He said: "Christian leaders and local Muslim leaders are working with the local population to encourage the ending of fighting and reconciliation and dialogue between different factions - and some of these people are giving their lives for it."
He went on to defend the delegates meeting with President Bashar al-Assad, saying it is vital to take the opinions of everyone into account so that the country can move forward.
The church leader also warned of peace not coming fast enough: "If the violent extremists prevail in the country, Christians with either be completely out of the country, or they will be killed."
He said: "What they're terrified of, they do not want to lose the pluralistic, diverse society, for which Syria has been famous for centuries and centuries, where the communities have lived together, where Christians and Muslims have coexisted."
Listen to Premier's Hannah Tooley speak to Rev Andrew Ashdown here:
