The decision comes only weeks after qualifying events in Africa, the Americas, Europe and Oceania were cancelled, with the remaining spots determined via world ranking points.
The World Youth Cup was scheduled to be held in Suva in June, with Fiji, Samoa, Tonga and the Cook Islands set to represent the Pacific.
But the International Netball Federation said, given the ongoing uncertainty because of the Covid-19 pandemic, including the risk to people's health, restrictions on global travel and quarantine requirements, the decision was made to postpone the event.
The governing body will now consult with the 20 competing nations about options for re-scheduling the event, including dates towards the end of 2021 and early 2022.
Fiji finished fourth at last World Youth Cup in 2017 and the country's Minister for Youth and Sports, Praveen Kumar Bala, said the government remained committed to hosting the tournament.
"We remain committed to the sporting aspirations of girls and young women in Fiji and across the netball world," he said.
"We look forward to hosting this event at an appropriate time when the world is a lot safer, international travel restrictions have eased and when all teams, and Fiji as your host nation, are certain of reaping a just return on their investment into the NWYC 2021."