Jacinda Ardern and her partner Clarke Gayford have been swamped with congratulatory messages from around the globe.
American-based New Zealander Heather McCracken started the #KnitforJacinda trend when she tweeted: "I woke up this morning feeling like 'I want to knit for Jacinda's pepi (baby in Maori) WHO'S WITH ME.'"
The 37-year-old, who was sworn in last October, made global headlines when she slapped down pre-election questions over whether she intended to start a family, insisting pregnancy had no bearing on a woman's career opportunities.
The prime minister's office confirmed that the ginger and white rescue cat, also described by Jacinda Ardern as the PM (Prime Moggy), died in an accident on Tuesday.
Australia on Sunday snubbed New Zealand's renewed offer to resettle 150 refugees held at remote Pacific camps, despite the closure of one detention centre in Papua New Guinea.
Jacinda Ardern gave a glimpse about what the country can expect from the new coalition, with policy agreements to be released early next week.