Mr Park pulled out the Wainoni Avonside Community Services Trust debate an hour before it was to begin, causing criticism from organisers.
He told The Star he withdrew due to a "critical," "personal" meeting.
Mr Park would not say what the meeting was for.
On Thursday he said he contacted the organisers to propose a make-up meeting on September 25 after missing the debate.
Mr Park said the criticism he had received for missing the debate was "unfair."
"I don't think it's fair at all. One instance where I couldn't make a meeting and yet, I've committed to being out there in the east and have been out there on several occasions.
"I can't undo something that happened and was unavoidable and I had to be at the other meeting."
Mr Park attended the Canterbury Employers' Chamber of Commerce debate on Wednesday night.
At the debate he questioned why the council was spending millions on cycleways when roads in the east needed fixing, labelling it as "not bloody good enough."
However, his last-minute withdrawal from The Wainoni Avonside Community Trust's debate earlier in the day was described by organiser Betty Champan as a "slap in the face" for people in the east wanting roading and other improvements after the earthquakes.
Former mayor Garry Moore, who chaired the debate, also criticised the no show.
Mr Park has promised during his campaign to improve conditions in the eastern suburbs if he is elected mayor.
In a Facebook post, Mr Park also criticised a Dalziel-led council for neglecting the east and failing to look after the basics.
Said Mrs Chapman: “It’s a bit of a slap in the face because a lot of people were here today to see Darryll. Out in the east, we know Lianne, she had been our MP for years, the people came to see Darryll to hear what he had to say.”
About 60 people were at the debate.
Mr Moore questioned Mr Park’s commitment.
“To me, that showed no commitment to being mayor because if you are running for mayor you have to go to every meeting,” he said.
Mr Park’s absence put a real dampener on the debate, he said.
“Is he only prepared to talk to the business community and not the people of town?”
Ms Dalziel said she thought the debate went well.
