Migrants from Malaysia, Bangladesh, Indonesia, Pakistan, Turkey, India, Jordan and Saudi Arabia are believed to be among those who have either been killed or injured by the attacks.
Many had come to New Zealand with dreams of one day getting residency for themselves and their families.
Canterbury District Health Board chief executive David Meates confirmed 34 attack victims were being treated, including 12 in intensive care in a critical condition.
"These are unprecedented circumstances for everyone and INZ is committed to ensuring we do all we can to support those who have been impacted," Elms added.
Zain Ali, University of Auckland professional teaching fellow and former head of Islamic Research said the Islamic Friday congregational prayer, or Jumu'a, is compulsory for post-puberty males.
"They would have been fathers, brothers...and it wouldn't surprise me if most of them are breadwinners for their families," Ali said.
They are also likely to be the families' principal visa holders or applicants.