Super Rugby chiefs on Monday rubbished claims that three more South African teams could leave the competition to play in Europe as "simply wrong", insisting they remained committed to the southern hemisphere game.
The Wales Online website reported that the Durban-based Sharks would be the first to join the European PRO14 competition for the 2019/20 season, with the Lions and Stormers potentially following suit the next season.
The Cheetahs and Kings, who were cut from a downsized Super Rugby last year along with Australia's Western Force, already play in the PRO14 which includes teams from Ireland, Italy, Scotland and Wales.
South Africa's franchises are reportedly increasingly disillusioned with competing alongside teams from New Zealand, Australia and Argentina, in time zones spread across the globe.
But governing body SANZAAR said all its member unions were still on board and involved in an ongoing review to determine Super Rugby's future up to 2030.
"As part of this process the member unions have fully committed to the strategy and their future participation," SANZAAR chief Andy Marinos said in a statement.
"Any talk of a change to the stakeholder relationship and partners withdrawing, creation of new teams in new markets and trans-Tasman competitions is unsubstantiated speculation and simply wrong."
He said the review would "address the challenges facing our game and to clearly articulate SANZAAR's vision and purpose in terms of a sustainable future".
"Everything has been on the table - status quo, expansion, contraction, competition formats, etc - as part of our initial blue-sky thinking."
Last week, Australia's Fairfax Media cited a leaked paper titled "SANZAAR 2030 Strategy" as examining a push into North America, potentially as a contingency plan should South African teams jump ship.
It reportedly raised the possibility of a 20-team, four-conference format likely to feature at least one US team.
Attempting to gain a foothold in the lucrative but ultra-competitive US market would be a bold move for SANZAAR, particularly after the 18-team debacle.
The experiment, which ended this year after two seasons, added an extra three teams to the competition, including Argentina's Jaguares and the Sunwolves of Japan.
SANZAAR's strategy paper found the resulting competition was "confusing, lacked integrity and was ultimately not supported by fans, stakeholders and commercial partners", Fairfax reported.
Moving into new markets is seen as key to increasing television revenue and preventing cashed-up European clubs from luring top players.
Marinos said it was disappointing some of the review's initial work had been "taken out of context".
"Potential expansion into new markets for example should not be confused with only an increase in teams," he said.
"We are already in the process of taking the established product to new markets. Matches being played in Singapore, Hong Kong, Fiji and Samoa are examples of this."