Rupiah stepped down during the MMD NEC meeting held today at Chreats Golf View in Lusaka.
MMD National Chairman Michael Mabenga will act as interim president until the convetion.
And Spokesperson of the de-registered for ruling party Dora Siliya has said that the party will challenge the de-registration in the courts of law.
Ms. Siliya said that as far as the party was concerned, they were up-to-date with annual returns to the Registrar of Societies.
The further said the de-registration of the party was politically motivated and an assault on democracy.
The Registrar of Societies de-registered the former ruling party this morning for non-payment of K390m in renewal fees since 1991.
The Registrar of Societies further said he was writing The Speaker of National Assembly to declare all 53 MMD seats in Parliament vacant because the party has been de-registered.
The MMD have 21 days to appeal to the Minister of Home Affairs, Kennedy Sakeni, against the decision of the registrar of societies to de-register it.
Current president Michael Sata was once a the Chief Executive of the party during some of the years the party was not remitting statutory annual fees.