FIFA voted unanimously to expand the World Cup to a 48-team tournament in 2026 after a meeting in Zurich.
The new format will see the finals feature 16 groups of three countries before a 32-team knockout stage.
FIFA - led by president Gianni Infantino - has come under fire but FFA has welcomed the change.
"Australia is part of the Asian Football Confederation [AFC] where the most significant growth and investment is occurring and we expect this trend to continue over the coming years leading up to the World Cup expansion," Gallop said in a statement on Wednesday.
"As the quality of Asian football continues to improve, AFC Member Associations will justifiably deserve greater representation at the FIFA World Cup.
"In the meantime we will stay focused on achieving qualification for the Socceroos for next year's World Cup in Russia and we hope all Australians will get behind the team for their final qualifying matches."
Asian champions Australia are third in the third round of AFC World Cup qualifying, a point adrift of Saudi Arabia and Japan after five matches in Group B.