Thousands of Afghans have crossed into Pakistan
Ruud Lubbers, UN High Commissioner for Refugees, was speaking after visiting the border north of Quetta, scene of angry protests last week when Pakistani border guards tried to stop thousands of Afghans crossing.
Click here for map of the refugee situation
Mr Lubbers said the UN refugee agency, the UNHCR, was ready to receive more than 100,000 people fleeing the fighting in 15 camps on the Pakistani side of the border, if Pakistan let them through.
He said he hoped that Pakistan's government would become "a bit more flexible" on its present policy of only allowing war wounded, women and children to cross.
He is due to fly on to Islamabad to press his case with Pakistani Government officials.
They have so far remained unwilling to relax their policy, worried about the costs and potential for unrest of any flood of refugees.
Pakistan's President Pervez Musharraf has repeated his government's reluctance to open its border.
"The issue involved is that we already have two and half
million refugees. If we open the gates freely, we would get
about two million (more), that is our prediction," he said.
Mr Lubbers said the UNHCR was willing to let Pakistan carefully screen refugees arriving to ensure no Taleban fighters were among them.
After his talks in Islamabad, Mr Lubbers is due to fly to Iran on Wednesday.
Nearly three weeks into the US-led military campaign against Afghanistan, the true scale of the resultant refugee problem is still unclear.
What is known is that major Afghan cities like Kabul and Kandahar have already been emptied of much of their civilian population.
Conscription fears
Families are fleeing both the intense bombing raids and, it is reported, attempts by the Taleban authorities and by their foes in the Northern Alliance to forcibly enlist young men into their armed forces.
Last week, several thousand refugees forced their way across the Pakistan border from Chaman in Afghanistan, and several thousand more are being held in Taleban-controlled camps close to the border.
Initially the UNHCR voiced fears of a million or more refugees flooding into neighbouring Pakistan, Iran and the former Soviet republics to the north.
But so far, the numbers of displaced people actually reaching the official border crossings is far smaller.
Mr Lubbers also called on Pakistan to stop sending Afghans back across the border.
Mr Lubbers admitted a complete reversal of policy by the government was unlikely, but he has urged a compromise to allow families as well as vulnerable women, children and the elderly across the border.
