Mr Holmwood said he would be interviewed and the drama would include actors and some of the people involved.
"I think it's important we get a look at the final cut before they release it.
"I'm a bit over it now, but it is a major part of our history, I suppose."
Molenaar's father, Paul, 77, said he was not interested in taking part.
"I would rather not get involved because it's been such a nasty thing. It's affected us all very much."
Mr Diver said he understood the public wanted to know what happened.
"It was the worst day of my life. The fact you have to relive things doesn't help, but the main thing is to ensure it doesn't happen again."
Eastern district commander Superintendent Sam Hoyle, who led the police operation, supported the production.
"It's important we document accurately all the events of the siege and the days that followed, provided it's done with the proper respect for those who were impacted."
-NZPA