Tierney has outlined why the WRU continues to plan to reduce the number of professional teams which it says will help release money to invest in Wales’ development pathway.
“I think if we remain with the status quo we’ll continue to see uncompetitive regional teams,” said Tierney.
“As a result of that you potentially will lose benefactors over time, fan numbers will continue to drop, players won’t want to play there.
“So there’s lots of risks around this.”
Tierney could not answer when the final decision will be made, although stated in the EGM that a delay will harm Welsh rugby’s future.
The four regions – Cardiff, Ospreys, Scarlets and Dragons – will play in the United Rugby Championship (URC) next season but there are still no guarantees what happens next.
“I wish I could give information, and I keep getting asked that question lots of different ways, but I can’t give you a date at the moment,” Tierney said.
“We’re in complex processes and they are difficult decisions that are going to last a generation.
“We’ve got to make sure they’re not rushed, they are the right decisions and in the best interest of Welsh rugby.”
Tierney also confirmed the WRU is down £6m on forecasted ticket sales for the 2025 Autumn Nations Series and 2026 Six Nations.