The women's competition at the 2030 Rugby League World Cup is set to expand from eight teams to ten, while the men's field will grow from ten teams in 2026 to 12.
The International Rugby League announced the changes on Monday, along with plans for a tournament staged across five cities in the USA and Pacific.
IRL chair Troy Grant said the event would retain a five-week duration but use a different location-based format.
"The World Cup under its current format runs for five weeks and RLWC30 is going to be run in five locations across the Pacific and USA," Grant said in a statement.
The host cities have not been selected, and the IRL will consider their strategic placement and stadium suitability.
Grant said each city would host pool matches over multiple days, in a setup resembling Magic Round, before the tournament moved to another location.
He said all nations would be involved during three weeks of competition, followed by semi-finals and finals.
The precise format remains undecided, with nations invited to provide feedback at the IRL AGM and Congress in Sydney over the weekend.