Oxfam's humanitarian coordinator for the Middle East, Pauline Ballaman, has described the dismal conditions facing thousands of Syrian refugees.
Speaking to ITV News, she warned their hardship will only worsen in the months ahead unless more funds can be raised.
Oxfam says that some 670,000 people have left Syria since the crisis began in March 2011 but numbers have risen recently. In Jordan alone, the number of people crossing daily trebled in the past week.
The cold weather has seen an increase in the number of those suffering respiratory infections and pneumonia, according to the aid agency, which is distributing mattresses, blankets, heaters and gas oil to help new arrivals.
Oxfam has launched a £12 million emergency campaign to help those who have fled the on-going conflict in Syria.
The aid agency says a growing number of refugee families are in desperate need of assistance during the winter months.
Families have arrived exhausted and traumatised. Some have faced bombs and bullets to get here.
Now, they are trying to get through one of the most brutal winters in the last two decades with almost nothing. Most families have to rely on the generosity of relatives and neighbours.
Along with local organisations Oxfam is trying to help thousands of families through this difficult winter period; but we could do so much more if we had more funds.
Oxfam is launching a £12 million emergency appeal to help thousands of Syrian refugees. The charity says a growing number of families are in desperate need of assistance during the winter.
It is hoped the appeal could help up to 120,000 people who have fled violence in Syria and crossed the borders into neighbouring countries.
Barbara Stocking, Oxfam's chief executive, said a "global new deal" was needed to reverse decades of increasing inequality.
We can no longer pretend that the creation of wealth for a few will inevitably benefit the many - too often the reverse is true.
Concentration of resources in the hands of the top 1% depresses economic activity and makes life harder for everyone else - particularly those at the bottom of the economic ladder.
In a world where even basic resources such as land and water are increasingly scarce, we cannot afford to concentrate assets in the hands of a few and leave the many to struggle over what's left.
The world's richest 100 people earned enough last year to end extreme poverty for the planet's poorest people four times over, Oxfam said.
An "explosion in extreme wealth" was hindering efforts to tackle poverty, the charity said in a briefing released ahead of next week's World Economic Forum in Davos, Switzerland. Oxfam said the net income last year of the 100 richest people was 240 billion US dollars (£150 billion) in its report.
The briefing, called Releasing The Cost Of Inequality: How Wealth And Income Extremes Hurt Us All, noted that people in "extreme poverty" live on less than 1.25 US dollars (78p) per day. The charity called on world leaders to commit to reducing inequality to levels last seen in 1990.
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The break-up of the eurozone could cost the world's poorest countries nearly £20 billion a year in lost trade and investment - the equivalent of almost a quarter of global aid - Oxfam warned.
As leaders of the world's biggest economies prepare to meet at the G20 summit in Mexico, the aid charity warned that the woes of the single currency threaten the living standards of people well beyond the shores of Europe.
The eurozone crisis is set to dominate next week's G20 gathering, but Oxfam chief executive Barbara Stocking urged the leaders - including David Cameron - not to forget the needs of the world's poorest countries.
The TUC general secretary Brendan Barber has said the Department of Work and Pension's figures published today show that the previous government's investments made a "huge difference to reducing child and pensioner poverty". But Mr Barber also said:
There is a real danger that the vital headway the last government made into getting children out of poverty will now go into reverse.
Moving the goalposts on what constitutes poverty won't help improve conditions for children living below the breadline. Spending on tax credits and benefits took children out of poverty - now government cuts are sending them straight back.