Mustafa Usman Ismail announced the police plan in Abuja on Tuesday after talks with Nigerian President Olusegun Obasanjo - the chairman of the African Union (AU).
"The government of Sudan has about 40,000 Arab soldiers in Darfur plus 10,000 police so the AU... they are going to be for building confidence to encourage people to go to their homes," Ismail said.
"We are going to increase the number of police to maybe 20,000 police in Darfur."
In Khartoum, a senior Sudanese official said more police had already been sent to Darfur under an agreement with the United Nations to establish safe areas in the vast western region, but he put the total there now at 8000.
Minister of State for Interior Ahmad Muhammad Harun said their role was "to secure the camps for the displaced and to facilitate voluntary return".
Obasanjo put parliament on notice his country could send up to 1500 troops if necessary to the vast region as part of an African protection force.
The UN Security Council has given Sudan about two more weeks to prove it has made progress in improving the security situation or face unspecified sanctions.
UN special envoy Jan Pronk will tour Darfur with Sudanese officials between 26 and 29 August to check whether Khartoum has met its commitments to begin reining in the militias.
The UN will also want to see that aid workers' access to what the world body says is the world's worst humanitarian disaster, is ensured.
Pronk is expected to present his findings in New York around 30 August.
But the council will also get an interim report next Tuesday, despite objections from Pakistan that the extra briefing was intended to embarrass Sudan.