The on-going closure of New Zealand's immigration office in China because of coronavirus has left more than 13,000 visa applicants waiting for a decision.
The Beijing office decides half of all Immigration New Zealand's temporary visas.
Immigration New Zealand (INZ) has already transferred around 12,000 applications to other offices, but 13,400 remain in Beijing.
More than 6,000 are for people unable to travel to New Zealand because of restrictions.
INZ said it was working to distribute the remaining 7,200 applications to other offices, but processing times would lengthen.
It is reassigning 50 work visa staff to instead focus on student and visitor visas and immigrants are being advised to submit their applications as early as possible.
INZ's Beijing office, whose 130 staff decide around 10,000 visa applications every week, has been closed since Chinese New Year on 24 January.
"INZ has considered a number of options for managing the impact of the Beijing office closure on visa processing going forward," said its Associate Deputy Chief Executive, Catriona Robinson.
"However, regardless of what actions INZ takes, it is likely that processing times for visitor, student and work visa applications will increase in the coming weeks due to the drop in immigration officers available to process visas.
"Presently the wait times for allocation of Essential Skills (work) visa applications to an immigration officer is 10 days.
"Early modelling suggests this may increase by up to six weeks if no other factors change in the intervening time. INZ will continue to assess the actions we are taking over the coming weeks to manage this rapidly evolving situation."
Applications submitted without all the required documentation or which require further verification would take longer than usual, she added.