National Party leader Chris Luxon says rest homes, retirement villages and at-risk communities must be flooded with boosters if New Zealand is to withstand Omicron.
"I can go to any supermarket in many other countries in the world, and they are freely available."
He said if he were in charge, he'd be in frequent contact with district health boards to get detailed information about the resources needed to battle Omicron.
"There's a difference between talking about things, and getting things done.
"I used to run an airline and we used to think...about risk management," he added.
He said the Government was using too much spin and not taking enough action.
Luxon said most people were adhering to health guidelines such as mask-wearing, but a sluggish Government response was the reason these actions were still necessary.
He said the Government entered "go slow" mode over summer.
Ardern said there was not yet a clear lead on the index case linking the South Island family to the international border.
In previous local Omicron cases, such a link had been discovered.
"Our plan for managing Omicron cases in the early stage remains the same as Delta where we will rapidly test, contact trace and isolate cases and contacts in order to slow the spread."
She said overseas evidence showed Omicron was significantly more infectious than the Delta variant.
Ardern said the new strain was likely to create far more Covid-19 cases than at any time previously in the pandemic.