Despite this, Economic Development Minister Stuart Nash maintains the Government is "moving in the right direction".
"A lack of fit-for-purpose EVs on the market is a barrier for some agencies," he said.
"Transition plans show that EVs will make up around 25 per cent of the total fleet by the end of the 2025/26 financial year."
In December 2020, the Government announced new vehicles procured by its departments would need to be electric or hybrid, "where practicable".
At the time, there were almost 16,000 vehicles in the Government's fleet.
It came on the back of a previous commitment to ensure an emissions-free fleet by 2025 within the 2017 Labour/New Zealand First coalition agreement.
The policy rolled over when the Government declared a climate emergency this term, and is being funded through the $220m state sector decarbonisation fund.
From 2025, public sector agencies will need to draw from their own budgets to buy carbon offsets to cover any remaining emissions.
Through written parliamentary questions, and data analysis by the National Party, Newstalk ZB can also reveal more than 3000 vehicles purchased since the 2020 announcement have either been petrol, diesel, or petrol hybrid cars.
Some of those are likely to fall under the caveat of vehicles not being replaced with electric alternatives, because "their operational requirements or other circumstances require".
Figures show departments, including the Ministry of Education, Ministry of Social Development, and Kāinga Ora, have bought 1642 petrol hybrids, as well as 992 petrol and 375 diesel cars.
That's in contrast to 729 battery electric (BEV) and 143 plug-in hybrid electric vehicle (PHEV) vehicles.
In a statement, Nash said the Government was looking to "speed up" the transition, but the gap in availability means departments are looking elsewhere for now.
"'The percentage of EVs, both battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) has increased from 1.6 per cent to 7.16 per cent."
"As a response to a strained global supply of EVs, some agencies are taking the approach of purchasing petrol hybrids until there are EV options available.
"The fleet transition plans note that the petrol hybrids will be replaced by EVs in the next two to three years when there is an anticipated greater supply."
He said there were departments where the lack of appropriate options was most keenly felt.
"Particularly those with an emergency response function [requiring long battery range] and those requiring heavier vehicles [vans and utes] to transport heavy equipment."
National's Simeon Brown said the Government "would have known about supply constraints", as they announced the move during the Covid-19 pandemic.
"They've given zero thought to the practicalities required to transition, and what the right period of time should be for that."
Brown said he backed the initiative but wanted to see better planning behind it.
'We want to be ambitious, but you've got to match that with your ability to get it done."