UN Secretary-General Ban Ki- moon on Friday said he is "extremely concerned about the rapidly deteriorating humanitarian situation" in Syria as Syrian refugees face harsh circumstances due to the coming winter, and a need for greater financial support.

"The secretary-general is extremely concerned about the rapidly deteriorating humanitarian situation in Syria, where more than 5 million people urgently need help," said a statement issued here by Ban's spokesman.

The situation in Syria grows more dire every day as the Middle East country has been embroiled in a bitter conflict for some 22 months between the government and rebel forces.

"As a consequence of this situation, over 2 million people have been displaced inside the country and more than 540,000 Syrians have fled to neighboring countries," the statement said.

"This winter, many families are struggling to keep warm, without adequate shelter, warm clothes and heating fuel," said the statement. "Children make up more than 50 percent of the civilians affected by the crisis."

The UN Refugee Agency (UNHCR) estimates the number of Syrian refugees could double to 1.1 million in the next six months.

"The international community must do more to alleviate the suffering of millions of people in Syria and the neighboring countries," said the statement.

"Despite the growing needs, the Syria Humanitarian Assistance Response Plan (SHARP) and the regional Refugee Response Plan (RRP) for 2012 are underfunded, limiting the ability of UN agencies and their humanitarian partners to reach people who desperately need help," said the statement.

The response plans now require more than 1.5 billion U.S. dollars to cover the most urgent humanitarian needs during the first half of 2013.

Meanwhile, the statement said that the secretary-general will chair a high-level International Humanitarian Pledging Conference for Syria in Kuwait City at the end of next month to garner more financial support for humanitarian needs.

Ban "urges all member states to be generous in their pledges and is thankful to those who continue to support the humanitarian effort," said the statement.