Sam Mkhwanazi, the ministry spokesman, said: "South Africa supports the African Union deployment of peacekeepers, but South Africa, having contributed to the African Union and UN's other missions, is currently stretched.
"It would not be in the interests of either the UN, the AU and other missions where South Africa is involved if the country were to send troops to Somalia."
The AU has proposed to send about 8,000 peacekeepers to Somalia to bolster the interim government after Ethiopian troops pull out of the country, where they intervened against forces of the Islamic courts last month.
"Peace is possible if the interests of US and the Ethiopians are removed"
Ahmed, Bossaso, Somalia
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Mkhwanazi said Lekota and other officials were reviewing options for assisting the Somalia peacekeeping mission, which might include technical support, and would shortly advise Thabo Mbeki, the South African president, on their suggestions.
Nigeria said this week it would send a battalion to join the peacekeepers in Somalia. Malawi and Uganda have also said they are willing to contribute to the peacekeeping force.
Ethiopia has started withdrawing its troops but there are fears that the interim Somali government of Abdullahi Yusuf, which lacks a national power-base, may implode if that happens and the Ethiopians are not swiftly replaced.