It was the first time the long-running British television show has been screened at its new time, after being moved to make way for MasterChef Australia.
And within an hour of the kiss between characters Sophie Webster, a religious schoolgirl, and her friend Sian Powers, the network had received calls.
A spokeswoman for TVNZ said the network abided by the Broadcasting Standards Authority guidelines for that time.
The BSA advises that up until 8.30pm, broadcasters need to avoid screening material that would disturb or alarm children.
"We apply the broadcasting standards evenly and without discrimination so that a kiss is a kiss, whether it's between a same-sex couple [or] a man and a woman,'' the spokeswoman said.
Coronation Street's move to the earlier timeslot upset fans who sent TVNZ an avalanche of complaints about the soap being sidelined for the cooking reality show.
The online petition "Stop TVNZ moving Coro St from its regular timeslots'' has received more than 6000 signatures from people begging the network to keep showing it at 7.30pm.
The shift raised concerns that edits would be needed to remove racier content and allow for a shorter timeslot.
The spokeswoman said TVNZ expected to make "very few cuts'' to Coronation Street as it moved to its pre-news slot.
Media commentator Martin Gillman said that the show would now be in children's viewing time.
"And these days any soap opera is going to contain more and more adult content in order to attract viewers,'' he said.
Family First spokesman Bob McCoskrie said the organisation was generally concerned about television content leading up to the 8.30pm watershed.
Mr McCroskie did not see the episode, but said a lesbian kiss would not worry Family First.
"We're worried about shows' rising level of violence, language and sexual content,'' he said.
Mr Gillman said this was the "beginning of the end'' for Coronation Street as it would undoubtedly lose a large number of viewers from the time swap.
He said it was "just by chance'' that the first episode at the 5.25pm timeslot was so controversial.
