The options were detailed in a report to the Security Council obtained by AFP yesterday, two weeks after the council agreed to send a police force to the African country to help quell a year of violence there.
In the report, Ban said dispatching a force of up to 3,000 was "the only option that could provide some degree of physical protection to the population" but that the mission would take months to prepare and present logistical challenges.
The secretary-general said the council could also decide to send a group of 20 to 50 officers who would assess the Burundi police force and "help bring about concrete and measurable improvements in the respect for human rights and rule of law."
The council is under pressure to take action in Burundi where the descent into violence has raised fears of mass atrocities, similar to those that convulsed neighbouring Rwanda in 1994.
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Violence has left more than 400 dead and driven more than 250,000 people across the border.
Diplomats said the proposed force of 228 police officers appeared to be the best option, but it remained unclear if Bujumbura would accept that many officers.
The government has told the United Nations that it was ready to receive some 20 unarmed police experts, but would oppose any "large" UN police presence.