The report was partially released in October last year, and the full version only released in April under the Official Information Act by Te Puni Kokiri, which produced it.
Collins said the report called for a "two systems" approach to New Zealand's governance arrangements trying to set up separate education, justice and resource management systems "by stealth" - as well as a separate Māori Parliament.
She alleged the Government was already enacting recommendations without public consultation, such as the Māori Health Authority and Māori council wards, and called for Prime Minister Jacinda Ardern to reveal where she stood on the report.
The Act party has previously called on the Government to reject its recommendations.
Minister for Māori Crown Relations Kelvin Davis said he was disappointed but "sadly not surprised".
"It's a desperate speech from an increasingly desperate leader.
"Her speech is at odds with the recommendations in National's election review released less than a week ago, it's at odds with her Deputy Leader's comments in recent days on a Māori Health Authority and I'm sure it doesn't represent the views of many in the National caucus.
"The Government is focused on solutions to New Zealand's issues while the National Party continues to be distracted by internal divisions."
A spokesman for Prime Minister Jacinda Ardern's office said the report had not been approved by Cabinet and so did not represent Government policy.
Questions about the Government's position on the report recommendations went unanswered.
New Zealand signed up to the UNDRIP in 2010 through then-Māori Affairs Minister and Māori Party co-leader Pita Sharples, under a National-led government.
The report He Puapua is described by its authors as a "step towards creation of a declaration plan".
New Zealand is the first state in the world to start on a path towards implementing the declaration.
Current Māori Party co-leader Debbie Ngarewa-Packer said Collins was showing "political amnesia" by ignoring the fact her party was the one that signed New Zealand up to the declaration in the first place.
"They supported and endorsed this at the time, and knew it would require more work. This report is merely a continuation of that and other constitutional discussions had over the past decade - there is nothing new in it."
Rather than creating separate systems, Ngarewa-Packer said the report recommendations were about acknowledging the current systems had been designed to favour Pākehā over others, and this needed to change.
"It is about shifting the balance, not being exclusive. For 181 years we have tried it this way and we know it has not worked for Māori. It is time for a mature national conversation about what that shift looks like."
One thing Ngarewa-Packer did agree with Collins on was for the Government to be more proactive in explaining how it would respond to the recommendations.
"I think the Government needs to push on with this, show some strong commitment to addressing the disparities, and start a mature conversation as a nation, rather than leaving it to politicians."
However, Ngarewa-Packer said Collins' wider comments about Māori separatism were "race-baiting".
"She is using Māori and the fear of separatism to appeal to a voter base, while Māori are trying desperately to resolve issues that are killing us."
She said it would "end in embarrassment for her", as New Zealand had "matured" in this area and a lot of Pākehā were supportive of such ideas.
Collins said in response she was not "race-baiting", rather looking at the facts.
"I am not trying to appeal to anybody who is racist," she said.
"We think there needs to be a national conversation about this report and where it might take the country."
