Kalaba has also announced officially his position as President of the Democratic Party where he will be fielded as Presidential candidate in 2021.
Addressing the media in Lusaka today, Kalaba said he has now accepted the role of presidency of the opposition Democratic Party.
He also said that he would not challenge his expulsion from the Patriotic Front but concentrate on building Democratic Party.
His resignation paves the way for a by-election in Bahati Constituency.
On Sunday the Patriotic Front expelled Kalaba for alleged gross misconduct largely hinged on his anti-Patriotic Front statements despite having stayed on as lawmaker.