Canada is urging all the parties involved in the peace talks in Darfur to sign an agreement.

The Sudanese government has said it will sign a draft agreement, but rebel groups are withholding their approval as they push for concessions on security and power sharing.

Foreign Affairs Minister Peter MacKay says Canada has a role in the talks as part of a small team of negotiators that also includes Britain and the United States. Canada's UN ambassador, Allan Rock, is in Nigeria taking part in the negotiations.

Refugees in Darfur (CP file photo)

The main stumbling block appears to be rebel demands for greater power and wealth sharing.

Going into Wednesday's meetings, one of the rebel negotiators said the proposals needed work before they could be signed.

"The document presented by the mediation team for us does not reflect the aspirations of our people because the documents failed to take into consideration the real issues that could solve the problem and root causes of the problems in Darfur," said Ahmed Tugod, from Justice and Equality Movement.

Louise Arbour (CP file photo)

The deadline for a peace deal was extended on Tuesday as Western countries try to push the factions toward an agreement to end the violence.

• INDEPTH: Darfur

Two militant groups, the Justice and Equality Movement and the SLM, rejected an earlier deal, saying it didn't meet their needs for more autonomy for Darfur and better representation in the Sudanese government.

The militant groups, mostly non-Arab tribes, began fighting in 2003 against the Arab-dominated government.

The government has been accused of backing the Arab militias, known as the Janjaweed, which have been fighting the militants and are accused of rapes, murders and genocide.

The United Nations estimates the fighting has killed 180,000 people and displaced two million.

Meanwhile, the UN commissioner of human rights, Canadian Louise Arbour, said Wednesday the situation in Darfur has "not improved, and in many respects [is] worse than it was" than when she visited the African region, one year ago.

"I think the space for humanitarian work has been reduced in part by fewer contributions by the donor community, and I think also in part by legislation in Sudan that restricts the ability of NGOs [non-governmental organizations] - local and international NGOs - to deliver humanitarian assistance," she told reporters in Khartoum.

On Thursday, Arbour will travel to another trouble spot, Juba, in southern Sudan, where a peace accord between the government and the Sudanese People's Liberation Movement came into effect in January 2005.