A six-month amnesty and buyback scheme was put in place after gun law reforms - supported by all parties but Act - banned most military-style semi-automatic (MSSA) firearms in the aftermath of the March 15 terrorist attacks in Christchurch.
Following the first announcement, it was revealed that a new firearms register would help stop the flow of guns into the criminal underground's black market.
After that anyone caught still holding on to now-illegal guns and parts will be prosecuted and will lose their firearms licence, and also face up to five years in prison.
Deputy Commissioner Mike Clement who has overseen the buyback scheme assisted by Assistant Commissioner Tusha Penny, said police would not be lenient on anyone flouting the law.
Clement earlier confirmed there would be no extension to the amnesty period.
"Everyone with a prohibited firearm or part needs to hand them in or they will be breaking the law after the amnesty ends on 20 December 2019," he said.
"If you want compensation for your firearms, to keep your licence and don't want to be prosecuted, hand in your firearms now."
He had a message for all firearms enthusiasts.
"Surely this is not what you want – to be unable to enjoy hunting or the hobby you enjoy ever again?" he asked.
After the final collection events tomorrow police are expected to release the provisional figures for firearms and parts handed in and what has been paid for them.
As of October 31 just over 32,000 firearms had been bought back.
"The vast majority of firearms owners understand why we are doing this," Clement said then.
"To those that have yet to do so, the time is now and you have a number of options, so there are no excuses.
"I want to be very clear though. On 21 December, whether you are a licensed firearm holder or a gang member, if you are unlawfully and without authority in possession of a prohibited firearm you will be committing a criminal offence."
Police Minister Stuart Nash echoed Clement's message.
"I can tell you that I am not going to extend the buyback," he said recently.
"If people haven't handed in their banned firearms by the 20th of December, they will get no money and they will face up to five years in jail if we find them."
For more information on the collection events, modification and other options available to you or to seek help with the process, go to www.police.govt.nz or call 0800 311 311.