Wales could play at Wembley in the autumn if it is more profitable for the Welsh Rugby Union than hosting games behind closed doors at home.
Games postponed in the 2020 Six Nations because of the coronavirus pandemic are yet to be rescheduled, including Wales' final home match against Scotland.
Chairman Gareth Davies says the WRU is assessing all scenarios for games.
"We'll look at the options in Wales, then you've got the different scenarios of will there be crowds?" Davies said.
"The [Welsh government] First Minister [Mark Drakeford] even two weeks ago said there wouldn't be mass gatherings in Wales this year.
"So that can change, obviously, but I just think we have to have various plans in sight and that's what we're doing at the moment."
He said the governing body would have to look at playing at Wembley if crowds were allowed in England and not Wales.
Wales played at Wembley while their Cardiff home was being demolished and rebuilt as the Millennium Stadium, now renamed the Principality Stadium, before the 1999 World Cup.
The last of those games became a dramatic 1999 Five Nations finale win over England in which Scott Gibbs scored one of the most celebrated tries in the nation's history.
Returning there is an option as the WRU deals with a possible £50m hit to its finances caused by no income if games are not rescheduled.
Asked if returning to Wembley is an option, Davies told BBC Radio Wales: "That's a lot of speculation, but having said that I think it's a case of we're looking at all options.
"It's quite a unique position we're finding ourselves in in the sense that it's continual scenario planning.
"This week we've been on with the Six Nations, yesterday we were on with the British Lions and every aspect you look at, it's really down to scenario planning, but there is no certainty.
"So... it's a case of yes, looking at fixtures for the autumn; we'd obviously hope there would be games in the autumn first of all.
"Secondly, where do we play those? Obviously that is driven by crowds or not and if it's no crowds, then yes, we've got Parc y Scarlets, Rodney Parade or whatever you can play in Wales.
"I suppose if there were crowds allowed in England and not in Wales, which you know could be a scenario, so from a financial point of view I think we'd have to look at that."
Wales were scheduled to play a June Test in Japan before two more tours games against New Zealand, games that fell victim to rugby's global hibernation.
World Rugby remains hopeful of tour matches being rescheduled during the autumn.
Wales' autumn schedule originally included hosting Fiji and Davies says they and Japan could yet feature on a home schedule.
"There's no certainty that all the southern hemisphere teams will come up - if that doesn't happen there's a possibility we'll play a Six Nations competition plus two extra fixtures against Japan and Fiji," said Davies.
"Those are the two frontrunners. People are talking about South Africa and the Barbarians too, but we're looking at all our options.''
Global talks 'are slipping'
Talks involving World Rugby and leading clubs from Europe about a revamped 2020 calendar and the future beyond that have yet to be finalised.
Leading clubs in England and France are resisting a calendar revamp that would see their domestic leagues play during summer months.
A 30 June deadline had been set for the sport's future to be settled, including when the 2021 Lions tour to South Africa would take place.
"Things are slipping, I will say that," said Davies.
"We were hoping to have decisions, say, on the Lions tour for next year by 30 June.
"But again there are other moving parts that's now pushed that back a couple of weeks, so there will be slippage in this.
"And I think everybody's keeping an eye as well on the progress that is being made in controlling the virus.
"The positive is that the north and south have been talking and are generally in agreement in terms of how the international calendar could look.
"Obviously there are other factors coming into it now, in particular the French and English domestic leagues in particular."
He added: "This is an opportunity and if it's not taken now you almost think well it can never be taken."