The two women were taken to hospital in a serious condition after the incident on Saturday, he said in a statement.
They were allegedly shot by Inkatha Freedom Party supporters.
The National Freedom Party was formed in a breakaway from the IFP.
Provincial police spokesmen Captain Thulani Zwane and Colonel Jay Naicker could not be reached for comment.
Mchunu condemned the incident and called on the leadership of all political parties to ask their supporters to respect the right of other parties to campaign freely in the province.
He said there were also reports on Friday that NFP members were allegedly blocked by African National Congress supporters while attempting to campaign in Ntshongweni, west of Durban.
“Political parties and its leadership owe it to the province, and indeed, the people of KwaZulu-Natal, to ensure that their members do not do anything that is going to reflect negatively on the image of the province,” said Mchunu.
“As we prepare for elections 2014, all the eyes of the country will be focused on KZN to see if we have, indeed, totally abandoned the culture of political intolerance and the practice of no-go areas.”
Mchunu urged citizens not to reverse the gains that had been made or undermine the political maturity that had been shown during the recent by-elections in KwaZulu-Natal.