Minister Lindiwe Sisulu says as the SADC enters its 26th year, there is a critical need for industrial development underpinned by a sound infrastructure.
Foreign correspondent Peter Fabricius says the root cause of the violence in the mountain kingdom is the involvement of the military in politics.
The regional body is sending a fact-finding mission to Lesotho to "avert the possibility of a further deterioration of security".
Foreign nationals protested outside the Department of International Relations and Cooperation in Pretoria.
The 15-nation group has highlighted that overall political stability still remains a priority as SADC grows into a significant economic bloc.
Joseph Kabila’s constitutional mandate as president ran out last November.
The organisation revealed today that more than one million children in Africa are malnourished.
Leaders are looking particularly at the case of unaccompanied migrants.
President Robert Mugabe criticised workers who seek new lives in Johannesburg and other SA cities.
The recent violence, which left seven people dead, is expected to be featured at the SADC summit in Harare.
The alleged mercenaries have reportedly accessed a stash of weapons waiting for them in Lesotho.
Amid major concerns over Lesotho, the activation of the Africa standby force will be discussed at the AU.
The Zimbabwean president will take over as chair of the regional body in August.
Ministers, non-governmental organisations and World Bank representatives are attending the gathering.
