It says it is obligated to be financially sustainable and it is facing the samed economic challenges as the rest of the country.
The organisation's change proposal, leaked to RNZ, says 66 roles would likely go from the workforce of 528 people.
About a third of the roles are already vacant, with both science and back office jobs likely to go.
GNS says it is supporting its staff through the unsettling and uncertain time, but it will continue to deliver the critical science, innovation, and technology.
"Growing our financial sustainability is critical if we are to make strategic investments - in our people, and in the assets, technologies, and capabilities required to deliver our critical science and science services now, and for years to come," GNS Science chief exectutive Chelydra Percy said.
"We have been focused on operating with fiscal prudence, seeking cost savings where possible and looking hard at any discretionary spending. Now, considering the size of our workforce alongside other cost saving measures is a difficult but necessary step on a longer journey to financial sustainability."
It wants staff input on the proposal.
Union claims cuts at GNS takes science jobs axed to 400
Public Service Association Te Pūkenga Here Tikanga Mahi assistant secretary Fleur Fitzsimons said GNS Science was proposing to cut more than 10 percent of its workforce.
She said it would undermine its critical work helping New Zealand adapt to climate change and manage natural hazards and risks from earthquakes, tsunami and volcanic eruptions.
This would take total roles lost in the science and research sector to well over 400 as detailed in the Save Science Coalition report.
"This is a sad day for science in Aotearoa and just more proof of the low value this government places on science and research," she said.
"The proposed cuts make little sense when GNS was profitable only a few months ago. On 1 March the chief executive told staff: 'Our financial results - yet to be audited - are positive. We are up on revenue and sitting at a profit. Overall, we're in a much better position than we were at this time last year.
"Like cuts at Callaghan Innovation, NIWA and elsewhere, this is happening in the absence of a science strategy from the government which is being prepared by Sir Peter Gluckman's Science System Advisory Group."
