The package will support the delivery of both next year's home men's World Cup and the 2029 women's showpiece but will also help fund legacy projects focused on the women's game in Australia and competition in the Pacific.
It follows the Australian government's $600m investment rugby league in the region.
In addition to a major investment in the PNG Chiefs, set to launch in the NRL in 2028, the 10-year funding package includes $250m to grow the sport in Tonga, Samoa, Fiji and PNG.
Rugby Australia boss Phil Waugh was in Brisbane on Wednesday to spruik the federal government injection ahead of the World Cup events.
"Rugby is the game of the Pacific, always has been and it's important to preserve that," Waugh told AAP.
He said the funds would help facilitate development programs, coaching and facilities.
The injection follows a separate $150m proposal to the federal government, led by the prime ministers of Fiji, Samoa and Tonga, for two new Pacific sides to join the four Super Rugby Australian franchises in their fledgling pre-season tournament.
Those sides would not be a reincarnation of the axed Moana Pasifika, an Auckland-based side forced out of the Super Rugby Pacific competition when their ownership pulled funding beyond this year.
The Fijian Drua were also introduced in 2022 but had the benefit of three seasons in the now-defunct, second-tier National Rugby Championship.
"In addition (to the $90 million) there's the proposal in with the Australian government with the prime ministers of Samao, Tonga and Fiji, which is direct investment to support rugby union in the pacific and in a lot of ways replicate the progress we've made with the Drua, since their entry into the NRC," Waugh said.
"Competition on island is really important and we've seen a great example of what can be done.
"There needs to be pathways on island.
"Keeping young boys and girls at home with their families, but offering the pathway to represent their country and also travel the world through rugby."
Next year's Rugby World Cup, which begins in October, is expected to bring 250,000 supporters to the country and generate $2 billion in economic activity.
Rugby Australia are determined to capitalise, with Waugh flagging an increase in grassroots and community investment to help surge registrations by 30 per cent and boost female participation by 70 per cent before 2030.
"Australia has a once in a generation opportunity to supercharge rugby union, both at home and across the Pacific," World Rugby chair Brett Robinson said.
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