Medsafe has requested additional information from Janssen ahead of making a decision about whether to approve the pharmaceutical company's Covid-19 vaccine.
In a statement, the Ministry of Health said New Zealand's medicines regulator - which has been considering the vaccine for approval since Tuesday - was delaying its decision which had been expected today.
The US, EU and South Africa temporarily halted use of the Janssen vaccine in the past few days over concerns about a rare type of blood clotting.
Medsafe group manager Chris James said the regulator expected to provide an update on the vaccine, which is produced by US company Johnson & Johnson, in the next two to three weeks.
"After receiving information from the US Food and Drug Administration (FDA) related to cases of blood clots reported in the US, Medsafe has issued a number of additional requests for data from Janssen. The pause of the rollout in the US and Europe has also been discussed with Janssen," the statement said.
"This will allow us time to investigate the data we receive so that when we do make a decision, we can reassure the New Zealand public about the safety and efficacy of the vaccine."
However, a vaccinologist told RNZ that Covid-19 was more likely to cause blood clotting than the vaccine.