"The first is the reduced trade and revenue for a lot of businesses over the last eight months as result of the Covid-19 restrictions, so businesses are looking to increase their flexible workforces.
"Also, we are all as an economy not really sure about what's coming in the next year, so businesses are keen to keep the flexibility they now have ... so they can accommodate any future lockdowns or future trading restrictions like the ones we saw this year."
The report showed the number of new permanent contracts shrank by 12 points to 67 per cent, but Thrush Marsh said that did not mean full-time staff were being fired for casual workers.
"Permanent employees are actually having their employment ended less frequently, so it's certainly not the case that permanent employees are being fired or made redundant and replaced with casual or fixed-term employees, but any new job that potentially would have gone to permanent are at some level being diverted to casual and fixed-term arrangements at the moment."
Thrush Marsh said she expected casual and fixed-term hiring to drop to levels seen in previous years once firms could return to pre-Covid-19 trading.
The hospitality industry saw the steepest increase in casual contracts, while the public sector recorded the largest increase in fixed-term contracts.
- RNZ