Al-Mazraq, Yemen  - A top United Nations humanitarian chief said on Friday the UN would try to establish contacts with the Shiite rebels in north-western Yemen to secure passage for aid agencies to civilians displaced by the ongoing rebel-army fighting.

"Access to all the IDPs (Internally Displaced People), in all the different areas where they are, is the biggest problem we have at the moment," the UN Under-Secretary General for Humanitarian Affairs and Emergency Relief Coordinator, John Holmes, said.

"I will certainly be talking to the government about that," he told reporters during a visit to a refugee camp for people displaced by the fighting in the north-western Yemeni provinces of Saada and Amran.

The camp, located near the border with Saudi Arabia, houses around 8,000 people, most of them women and children forced to leave their villages after the army launched its latest offensive on the rebels, known as Houthis, two months ago.

"And we will need to find a way to find some contact with the Houthis to convince them that this is what we need to do as well," Holmes said.

He said there would need to be several humanitarian corridors because the displaced people are trapped in different areas.

Government troops have been battling thousands of armed rebels in rugged mountains overlooking the borders with Saudi Arabia since August 11, in the latest flare-up in the fighting that has raged on and off since mid-2004.

Two truces designated for allowing humanitarian aid have since collapsed.

Hundreds of insurgents, troops and civilians have been killed and around 150,000 people were forced to leave their villages during the past five weeks, according to UN estimates.

Authorities accuse the Shiite group of seeking to restore the rule of the Zaydi royal family, which was toppled by a republican revolution in 1962.

The Houthis say they are in revolt against government corruption and the Yemeni alliance with the United States. (dpa)