"All our assistance will be carefully calibrated and monitored as well as legal, and will be aimed at saving life, alleviating this human catastrophe and supporting moderate groups."
It came as the number of refugees fleeing the country reached what he called the "sad milestone" of one million refugees.
The UK is also taking advantage of the embargo relaxation to provide assistance, advice and training to the Syrian National Coalition. Equipment for search and rescue operations and communications will also be sent along with incinerators, rubbish collection and water purification kit to prevent the spread of disease.
Mr Hague said the UK had fought hard to secure the changes to preserve an EU-wide approach but cautioned: "We will have to be ready to move further, and we should not rule out any option for saving lives."
It came as the chief of staff of the rebel army in Syria was in Brussels, urging the international community to supply it with arms and ammunition to help fight the regime of President Bashar Assad. At least 10,000 people have been killed in the brutal civil war in the last two months, Mr Hague said - more than in the whole of the first year since uprisings were brutally suppressed in 2011.