Future Wales Six Nations games being broadcast free-to-air on Welsh language channel S4C is "non-negotiable", according to Welsh Rugby Union (WRU) chief executive Steve Phillips.
Private equity firm CVC has acquired a 14.3% stake in Six Nations Rugby.
The current Six Nations deal with the BBC, ITV and S4C ends in France v Scotland's 2021 finale on Friday.
"It is absolutely critical that we land S4C coverage here," said Phillips of negotiations for the next contract.
"That is non-negotiable for the Six Nations and I think all my colleagues in the other unions have made it very clear on that as well.
"We have taken a similar view with the Pro14 (S4C live games). So, S4C having Welsh rights is fundamental to us in the Six Nations and the autumn.
"Last year with England in the autumn you could watch it live on S4C or on Amazon."
BBC Wales currently produces S4C's Welsh language coverage of Wales games.
CVC's investment has still to be approved by regulatory authorities and Phillips does not expect that to happen until August or September, 2021.
The company already has stakes in Pro14 and the Gallagher Premiership. It will invest up to £365m for a 1/7th share in Six Nations Rugby, working alongside the rugby unions of England, France, Ireland, Italy, Scotland and Wales.
The money will be split on a sliding scale between unions, with the Rugby Football Union - England's governing body - receiving £95m and the WRU £50m, which Phillips has recently welcomed.
Six Nations Rugby includes the Guinness Six Nations Championship and the autumn international fixtures.
CVC's involvement has led to speculation that high-profile rugby tournaments will only be available to view behind paywalls.
Phillips has been confirmed as WRU chief executive, having held the role on an interim basis since September.
His main focus in that time has been dealing financial difficulties in the game caused by coronavirus.
Phillips negotiated a £20m loan for Wales' four regions to secure their futures, which has to be repaid over a five-year period.
The £20m is from the coronavirus large business interruption loan scheme (CLBILS), which gives NatWest Cymru an 80% guarantee from the UK government against the outstanding balance of the loan, but "the borrower remains fully liable for the debt".
In November, the UK government pledged £135m to rugby union in England as part of the £300m winter survival package.
Provisionally the Rugby Football Union (RFU) - which governs the sport in England - was set to receive £44m, Premiership Rugby clubs are expected to get £59m, Championship clubs £9m and community clubs £23m.
Rugby union in Scotland will receive £20m. Of that £5m is in loans and £15m in grants.
The loans in Scotland and England are repayable over 20 years and Phillips hopes to renegotiate the loans to the Welsh regions and with that repayment timescale.
"There was nothing in the recent [UK government] Budget about CLBILS being extended (term period) and that was the opportunity to do so," said Phillips.
"Our efforts are now focused on our discussions with Welsh Government which are very positive and cognizant of what the UK government and Scottish Government have done."
Phillips added: "The first repayment [for the regions] is due in the first week of July so we are trying to work to that timescale.
"If we were to drift then because of process I could see a scenario, subject to board approval, where we might step in and try and help with that and pick it up again later, but I am confident of landing something with Welsh Government, but we need to go through the process."