Progress could be made against Bashar al-Assad's regime even if it refuses to accept Kofi Annan's six-point plan, UK politicians are hoping.
Foreign secretary William Hague is attending an international Friends of Syria meeting in Istanbul this afternoon, where 75 countries are discussing the current situation.
They are hoping the Syrian government will implement the terms of the Annan plan agreed to five days ago. This calls for a ceasefire and the withdrawal of troops and artillery from population centres, as well as access for journalists and aid workers and the release of prisoners.
The Annan plan has the endorsement of all UN security council states - including Russia and China, which had vetoed earlier resolutions criticising the Assad regime.
Syria's government has shown no signs of implementing the plan so far. If it does not Damascus' intransigence could pave the way for the security council unanimity so far not yet achieved.
"I hope every nation represented here will adopt the sanctions that the European Union, United States and others have already imposed," Mr Hague said in an intervention at the meeting.
"If all of our countries adopted these measures, in particular asset freezes, ending purchase of Syrian hydrocarbons and supplies for the Syrian military the impact would be very great."
Earlier he told BBC1's The Andrew Marr Show that Damascus did not have an "unlimited period of time" to adopt Mr Annan's proposals.
"Everything the Assad regime has done looks like stalling for time. On the other hand, what is now being put to them is a plan being put forward by the whole UN security council," he said.
"If the Assad regime fails to go along with this plan, then they are in defiance not only of what we have said, but also what Russia and China have supported as well."
Shadow foreign secretary Douglas Alexander made clear Labour backed Mr Hague's approach, saying he was "in sympathy" with the Foreign Office's views.
Referring to the Syrian government, he told Sky News' Murnaghan programme: "You don't judge them by their words, you judge them by their deeds."