A company spokesperson told iTWire that Optus was in the process of updating the Optus Sport app so that Australians could access it free.
As of Friday morning, all content is still behind a paywall.
iTWire had pointed out on Thursday that while Lew's announcement had been made at 5pm on Wednesday, World Cup football content on Optus Sport was still behind the paywall.
The spokesperson said that it would take some time to change the billing in the app stores.
"But be assured (that) anyone who purchases a subscription via App store or Google Play will be refunded over the next coming weeks," the spokesperson added.
Optus was forced to ask public broadcaster SBS to simulcast all group games in the World Cup after its streaming service encountered some difficulties in the first few days of the tournament.
The last group matches, pitting England against Belgium and Panama against Tunisia, both in Group G, are scheduled to be played at 4am AEST on Friday. The round of 16 is set to start on 1 July.
Optus had obtained the rights to stream all 64 games, while SBS was to show all games involving Australia, one match a day on other days, the semi-finals and the final.
But on 19 June, Optus said that SBS would simulcast games over the next two nights, due to technical difficulties it had faced.
The announcement about SBS simulcasting the remaining group games was made on Wednesday.