Many Optus Sport subscribers have struggled or been unable to watch live games due to problems with weak connections over the tournament's opening round of matches. 

Optus chief executive Allen Lew has vowed to use the two days of simulcasting to find a "robust solution".

"We have a dedicated team that have been working around the clock to attend to the technical issues," he said.

"The demand is no reason for us to make the mistakes that we did over the weekend so I apologise for that."

SBS managing director Michael Ebeid has said that, if the technical issues are not fixed within the 48-hour window, then the simulcasting could be extended.

He insisted that there are no plans to do this so far.

"At this stage, Optus is saying they've fixed the problem," Ebeid said.

"We'll see how it goes over the next two nights and then we'll together - as partners and broadcasters - we'll reassess, and if we need to continue [simulcasting] we'll make that decision at the time."

Free-to-air broadcaster SBS has kept rights for 25 of the 64 games, including all three group matches involving Australia.

All other games are only available via a paid subscription for Optus.

The highest number of complaints surrounded the Group A clash between Uruguay and Egypt on Friday (June 15).

Australian Prime Minister Malcolm Turnbull has even become embroiled in the dispute after phoning Lew today, who reportedly assured him the problems would be swiftly resolved. 

"I had a call with Allen Lew, with Optus, to seek his assurance that the failures in the streaming service have been rectified," he said.