At least 28 countries around the world have agreed to take in more than a 100,000 Syrian refugees, the head of the UN refugee agency has said.

"Today, 28 countries expressed their solidarity with the Syrian refugees but also with the five neighbouring countries which are hosting them... offering what we estimate will be more than 100,000 opportunities for resettlement and humanitarian admission," Antonio Guterres told reporters after a high-level pledging conference in Geneva on Tuesday.

The pledges come days after rights group Amnesty International said that a number of affluent nations have taken in a "pitiful" number of the million of Syrian refugees uprooted by the country, placing the burden on Syria's ill-equipped neighbours.

The UN reported in August this year that more than three million Syrians have fled the war-ravaged country, an increase of one million since August 2013. 

In addition to those who fled, the UN says more than seven million Syrians are internally displaced.

The refugees face poverty, illness and growing tensions with host communities in their already-impoverished temporary homes.

Half of Syria's population has been displaced since anti-government protests that began in 2011 escalated into a civil war.

Source: Al Jazeera and agencies