The former Prime Minister's chief science adviser Sir Peter Gluckman says the immediate action against Covid-19 might have "been the easiest part".

He is appearing before the Epidemic Response Committee which is today analysing the social impact of the pandemic and the lockdown.

The committee, chaired by National leader Simon Bridges, was set up to empower MPs to scrutinise the Government's response to Covid-19 in the absence of Parliament.

Gluckman said the past few weeks had left "indelible marks" on our society.

"The Government has done much that is very good under serious pressure but this may have been the easiest part," Gluckman said.

Many Kiwis will have had their certain futures ripped away from them and will mean an increase in fear, anxiety and frustrations emerge, he said.

Gluckman said there would be a lot who are newly vulnerable, for example a 55-year-old travel agent now out of work and without a future, who would join New Zealand's large number who were already disadvantaged.

New Zealand needed to make sure we have "more inclusive discourse" about how we rebuild our future.

Gluckman, who now heads think-tank Koi Tū: The Centre for Informed Futures, said we were not yet at the peak of the distress from the lockdown - that will come in the next few weeks.

Based on other disasters, about 10 per cent of the population would develop depression and there would be some who are suicidal, he said.

Marijuana was now the main way people are managing stress in South Auckland, Gluckman said he'd been told.

The primary need now was to support the social services providing help and solutions to our communities and the focus had to be on how to mitigate the effects of the crisis.

Gluckman said Maori were disappointed and excluded by not being included in the room of decision makers, and giving them a seat at the table would be useful.

Despite not being included, they'd done well with iwi providing food distribution and checkpoints, he said.

There would also be a "massive increase" in young people wanting to go to university and there'll be a big increase in demand from overseas students as New Zealand is seen as safe.

Now was not the time to be shrinking our universities, he said.

The Government also needed to release more data to give people more certainty in uncertain times.

"The more that we can give certainty to the people, the better."