The National Party is calling for a Royal Commission of Inquiry into a lack of preparation for the Delta variant of COVID-19 arriving on New Zealand's shores.
It comes after 160 new community cases of COVID-19 were reported on Saturday - the worst day of daily infections since the pandemic began.
Experts have said New Zealanders should expect those case numbers to rise in the coming days.
National Party leader Judith Collins said the Government went "all in" on its elimination strategy, assuming it would work to beat the Delta variant.
"While other countries were vaccinating as quickly as possible and investing in contact tracing, rolling out saliva testing and utilising rapid antigen testing, New Zealand followed the same playbook that worked in 2020," she said in a statement.
She called for a Royal Commission into the Government's preparations, to understand why New Zealand didn't adapt or evolve its COVID-19 response.
COVID-19 Response Minister Chris Hipkins said earlier this week the Government was "acutely aware that the virus is continuing to mutate and that there are new variants of the virus emerging and we've continued to plan for that".
But Collins said New Zealand's slow vaccine rollout was a "public policy disaster" and "there must be accountability".
Hipkins, speaking to reporters on Thursday, said the Government did plan around the virus becoming more infectious.
"There have been other variants of the virus, prior to Delta, which has also caused us to re-look at our settings as well. So I want to push back on the notion that work wasn’t being done around to continuing to strengthen our defences against COVID-19 prior to the word 'Delta' being mentioned."