Police Minister Poto Williams says the number of names on the police's gang list has gone up "about 60" since they were last publicly released in May.
There were 8003 people on the list then, a rise of 2435 since Labour came to power in 2017.
Earlier this week National accused the Government of hiding the numbers, saying Williams was "deliberately withholding the latest batch of information".
"Either the numbers have increased significantly again or the Government is trying to covertly adjust the way they measure the number of gang members in New Zealand," said police spokesperson Simeon Brown.
"This deliberate attempt by the Police Minister to withhold the data shows that she and Labour do not want those numbers out in the public domain."
Appearing on Newshub Nation on Saturday, Williams said the numbers go up because it's "very hard to get off the list" once you're on it.
"It's an intel tool. It's not something that's useful in terms of really establishing the gang picture."
An expert in gangs, sociologist and author Jarrod Gilbert, told The AM Show in February the number of supposed gang members - as measured by the police's list - was likely "heavily inflated", citing the same reason as Williams.
"It's incredibly easy to get on the [gang] list because the police identify someone wearing a patch and so their name goes onto this database. But if people leave the gangs - and so many people are - it's very, very hard for police on the street to identify when someone's left."
Gangs were also handing out patches more readily, he said.
The Police Commissioner has also said the list can't be used as an accurate measure of gang activity, as it was probably "only going to go in one direction".
The Opposition has repeatedly targeted the Government on the gangs issue lately, including its approval for a multimillion-dollar meth rehab programme run by a lifetime member of the Mongrel Mob, Harry Tam.
This week footage of Tam shot last year showed him urging other gang members not to vote for National and saying "sieg heil" - a phrase associated with the Nazis.
Williams said despite Tam's flaws, the rehab programme had been proven to work.
"Harry Tam hasn't talked about the harm that's caused to women and children who try to escape the gangs. Harry Tam hasn't talked about the harm that meth causes to communities. I mean, I don't buy necessarily all the stuff that Harry Tam and the like tell you… Gangs proactively recruit young people into them and I don't for a second, buy that.
"I've been saying all week that we are funding a programme that has been shown to work. We are not funding the gangs. I don't know how much clearer I can be."
She said the Ministry of Health evaluated the scheme run by Tam, and found it had 100 percent success rate in keeping people off the destructive drug. She wasn't sure how long after the programme people who went through it were checked on.
"The Ministry of Health is the lead agency on this, dealing with doing a programme that actually has been proven to work. We're not funding the gangs. We're funding the programme."
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