Six Nations chiefs admit the competition could go behind a paywall from 2022 but insist the tendering process is still at an early stage.
A report states that Sky Sports are favourites to secure the next UK broadcasting rights package in a deal worth in the region of £300m (€344m).
BBC and ITV are contracted to share all games until the end of the 2021 Six Nations but rules prevent them from making another joint bid.
It raises the prospect of the hugely-popular tournament no longer being free-to-air, but event organisers insists no decision has been made.
“Six Nations are in the process of seeking bids for various sets of media rights but these are not due for some time,” a statement read.
“All of this is highly premature and speculative as no proposals have yet been received by any interested party.
“We would not rule anything out at this stage and the unions will collectively review and make a decision based on the nature of the offers received.”
Virgin Media holds the rights in Ireland, but the tendering process for those has not yet reached the bidding stage.