KABUL, Nov 28 (Reuters) - U.N.-monitored disarmament commissions have collected more than 6,000 small arms and 30 tanks in the northeast of Afghanistan in less than three weeks, the United Nations said on Thursday.

Disarming local warlords and rival factions across the country is seen as a key to bringing stability to the country, where civilians are often armed after 23 years of civil war and occupation.

"We at UNAMA (U.N. Assistance Mission for Afghanistan) take note with satisfaction of the innovative approach to the disarmament that has been carried out in the northeast," U.N. spokesman Manoel de Almeida e Silva told a news briefing.

Covering the provinces of Baghlan, Badakhshan, Kunduz and Takhar, the disarmament programme targets individuals who are not registered with the defence ministry of the central government.

According to authorities in the northeast, more than 6,000 small arms, thirty tanks and 20 vehicles have been collected in Kunduz province since the start of the disarmament plan on November 10th, Silva said.

"Although there still remains several commanders that need to be disarmed, the security situation has reportedly improved since the beginning of weapons collection on November 10."

Silva did not have figures for the number of arms collected in the other three northeastern provinces. He said collected arms had been stored in local military bases.

The number of weapons handed in to commissions in Kunduz far exceeds attempts to disarm warlords and commanders in northern provinces around the key city of Mazar-i-Sharif, considered by many to be one of Afghanistan's most volatile areas.

There only a few hundreds arms have been gathered in two earlier attempts to disarm commanders loyal to rival factions led by Uzbek warlord Abdul Rashid Dostum and Tajik commander Ustad Atta Mohammad.

Silva said Dostum and Atta had collected 663 light and heavy weapons in Dara-i-Suf in the Samangan province and in Sholgara to the southwest of Mazar in the past week as part of a drive to disarm unruly commanders.

Dostum and Atta are key officials in President Hamid Karzai's government. They both swear loyalty to Kabul, and blame recent fighting in areas under their control on unruly commanders.

The government of Japan has pledged to spend millions of dollars on the disarmament process in the coming year through the United Nations, according to Afghan officials.