Diplomats from over 60 nations and the Arab League met in The Hague on Thursday to toughen and improve coordination of sanctions against the regime of Syrian President Bashar al-Assad.

"We need vigorous implementation," Netherlands Foreign Minister Uri Rosenthal told the opening of the "Friends of Syria" sanctions working group.

"Sanctions will only have an impact if they are carried out effectively. That is how we can make a difference."

The meeting comes after the European Union agreed earlier this month on the need to beef up sanctions against Assad's inner circle as the world struggles to resolve the bloody 18-month conflict.

The European Union and the Arab League have slapped sanctions on the Syrian regime, with embargos on oil and weapons as well as travel bans on members of Assad's family and his top brass.

"The regime and its trading partners try to get around sanctions," Rosenthal said. "So we need to work together with public and private partners, by sharing information and best practices."

Experts from the financial sector were also meeting in The Hague to discuss ways of bolstering economic sanctions, including through asset freezes.

"It's not a question of whether he will leave but when he will leave," Rosenthal said of Assad.

More than 27,000 people have been killed in violence across Syria since March last year, according to the Syrian Observatory for Human Rights. The United Nations puts the figure at more than 20,000.

The international community has struggled to find common ground on ways to halt the bloodshed, with Russia and China vetoing three UN Security Council resolutions providing for sanctions against the Assad regime.