"I have expressed that a one-week suspension of Parliament is all the National Party will support. However, the Prime Minister has indicated that she expects it will continue longer than that," Collins said.
The return of the House is technically up to the Speaker, Trevor Mallard, but the Prime Minister must first ask him for delay. The Speaker then has final say over when Parliament would next meet.
Parliament had been set down to return next Tuesday.
Ardern can only delay the sitting after she has consulted with other party leaders and received advice from director general of health Dr Ashley Bloomfield.
The House is currently in recess.
Last week, the Business Committee met to debate delaying the return of sitting.
It failed to come to an agreement, leaving Ardern little choice but to use standing orders, the rules that govern Parliament, to call for a delay.
The absence of debate in the House will not mean an end to all scrutiny.
Parliament will instead run a series of long select committee examinations of different parts of the Covid response.
Leader of the house Chris Hipkins said: "Ministers and senior government officials will be making themselves available to appear before virtual select committees over the coming week.
"Those meetings will be televised on Parliament TV and we expect Opposition members to have the bulk of the allotted time to ask questions," he said.
Minister of Finance Grant Robertson will appear before the Finance and Expenditure Committee on Tuesday morning, and Hipkins will appear before the Health Committee on Tuesday and Wednesday afternoon, taking questions on Covid-19.
These will run in a similar way to estimates hearings, when ministers and officials come to select committee to be grilled on various parts of their portfolio and spending.
But the Opposition has rankled at this, noting the Government effectively controls select committees. It chairs nearly every committee and has majorities on most committees, too - meaning less opportunity for scrutiny from the opposition.
The Speaker may write to select committee chairs urging them to allow the opposition more questions.
During the last lockdown, a special opposition-controlled committee was established to scrutinise the Government.
But because Parliament needs to meet to establish the committee, it has not been reestablished this time.