This was too late, as the harvest would be over by then, Rural Contractors New Zealand chief executive Roger Parton said.
O'Connor said the government had warned growers of the pressure on managed isolation rooms.
"We flagged to them in September that they needed to get on with this pretty quickly and use the space that was available then," he told The Country's Rowena Duncum.
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Space was tight due to Kiwis wanting to come home for Christmas, O'Connor said.
"At that time they were crying out saying they urgently needed those workers – we said that there would be some space leading up to Christmas in quarantine – but that space would be squeezed if New Zealanders wanted to come home."
Despite this, he encouraged growers to "get on, and get those people as quickly as possible."
Duncum asked whether it was a "kick in the guts" for growers whose livelihoods were at stake, to let people wanting to come home for the festive season take precedence over critical workers.
"New Zealanders have the right first and foremost," O'Connor said.
"Covid's been a kick in the guts for everyone across our economy – particularly people living offshore in some really difficult circumstances – they may have lost their jobs."
Covid-19 had made life difficult all over the world and O'Connor said it was easier to forget that in New Zealand "because we have got on top" of it.
"Sometimes I guess we take for granted that we can just carry on business as usual ... most places in the world it is not business as usual."
"These are trying times. We're trying to make sure that New Zealanders get cared for and can come back to their families, and a lot of those will miss out."
"The issue of workers for contractors ... we've helped them with a lot of training – there's been a lot of good work done, but there's still going to be pressure pretty much on every industry across our economy and across the world for some time yet."
Also in today's interview: O'Connor talked about his new portfolios and what he was going to focus on for New Zealand agriculture.