Human rights group, Amnesty International says tens of thousands of civilians in Sri Lanka's war-torn northern region urgently need humanitarian assistance, and is calling for access for international aid workers in the region.  As Anjana Pasricha reports from New Delhi, concerns about civilians trapped in the civil war have been growing as fighting has intensified in recent months.   

Rebels examine their weapons in this handout picture released by The Liberation Tigers for Tamil Eeelam (LTTE) website Tamilnet (file photo)

Amnesty International says more than 300,000 people, forced out of their homes due to fierce fighting between Tamil Tiger rebels and the military in the north, are in desperate need of shelter, food and sanitation.

In a statement Wednesday, the group said many of these people are living in camps controlled by the rebels, who prevent them from leaving for safer areas.

In mid-September, Colombo ordered humanitarian workers to evacuate the Wanni region citing safety concerns as an intensified military offensive led to some of the bloodiest fighting in recent years. 

The government said it will take care of the humanitarian needs of the displaced people, and has reiterated that it is looking after their needs.   

But the Deputy Program Director for South Asia at Amnesty International, Madhu Malhotra, says aid reaching the people is inadequate. She says many people face the threat of malnutrition and disease.

"We have no ideas whether whatever limited aid, food especially, which has reached the region, whether it is really being distributed," she said. "According to World Food Program, on average people are receiving about 1,000 calories per day, and this is short of half of the 2,100 calories required per day. This was based on recent weekly food convoys.

Amnesty's Malhotra says at least 20,000 families need temporary shelters to protect them during the approaching monsoon season. 

"People are staying in real bad conditions, they have torn up rice sacks to hang over bits of wood, desperate attempts to make their own shelters," she said.

Amnesty is not the only group to voice concern about the plight of the civilians in the north. A non-government body, the Tamil Rehabiltiation Organization, says air force raids and artillery shelling on the main highway leading to the Wanni region is hampering the movement of supplies meant for displaced people.

In recent weeks, the Indian government has also expressed concern about the increasing numbers of displaced people and the "suffering of the civilian population" due to the escalation in fighting in the north. It has dispatched food and medicines for the refugees, most of whom are ethnic Tamils. India has a large Tamil population in its southern state of Tamil Nadu.

Aid agencies and Amnesty International say the government should allow aid workers into the region to assess and provide the basic needs of the civilians in the war-torn area. Sri Lanka's civil war has dragged on since 1983, when Tamil Tigers began fighting for an independent Tamil homeland.