The Political Parties Disputes Tribunal ruled that the expulsion was null and void since the due process was not followed.
The Wiper Party has been told it cannot expel Machakos Governor Alfred Mutua and five other politicians.
The six were Mr Mutua, MPs Regina Nthambi (Kilome), Joe Musyimi (Mwingi Central), John Munuve (Mwingi North), Michael Kisoi (Mbooni), and Richard Makenga (Kaiti).
They had been expelled by Wiper in December last year, because they had attended the launch of the Maendeleo Chap Chap Party on August 25 and associated with it.
The Political Parties Disputes Tribunal said that it was not clear whether Wiper Party was using its 2012 or 2016 party constitution.
“Without proof that the 2016 party Constitution was properly in place, the tribunal can only infer that there was no clarity as to how the complainants would be duly subjected to party disciplinary processes,” said the tribunal in the judgement.
Governor Mutua and the five MPs had contested their ouster from Wiper on grounds that it was not made in compliance with the party’s laws.