Western Melbourne will be admitted to the A-League for the start of next season, with South-West Sydney is set come into the competition for the following campaign.
The official announcement was made by the FFA on midday (AEDT) on Thursday by chairman Chris Nikou, CEO David Gallop and A-League head Greg O'Rourke.
It's understood the two franchises have been chosen as 'preferred bidders', with four bids missing out - including Melbourne's Team 11, South Melbourne, Southern Expansion and Canberra.
These defeated bids will likely have a chance to enter the competition after the end of the 2019-20 season, if Wellington Phoenix do not meet certain criteria and fail to have their licence extended.
The addition of Western Melbourne for the 2019-20 season will likely mean an uneven 11 team competition with byes for at least one campaign.