The ANC-NFP coalition signalled a "dark day for democracy in KwaZulu-Natal," the IFP said on Monday.
The African National Congress and the National Freedom Party will hold coalition talks on Monday afternoon in Durban.
Independent Electoral Commission chairperson Brigalia Bam on Saturday declared the 2011 local government elections to be free and fair.
Voter turnout for the local government elections was the highest to date, IEC chief electoral officer Pansy Tlakula said on Saturday.
Congress of the People president Mosiuoa Lekota said he was satisfied with his party's performance in the local government elections.
Former PE mayor Nceba Faku has called on ANC supporters to burn down the city's Herald newspaper, during the party's election victory celebrations.
ANC voters have not crossed to the DA, despite an increase in the opposition party's share of the votes, said Cosatu's Zwelinzima Vavi on Friday.
The African National Congress won control of the Johannesburg Metro, receiving more than 1,2-million votes, the IEC confirmed on Friday.
The new NFP party in KZN has surprised even itself by gaining a share of the province's votes big enough to trigger some frenetic horse-trading.
Political parties' fortunes have waxed and waned in the past five years. We've contrasted some of the 2011 poll's trends with the 2006 results.