Australia have been forced to settle for silver medals in the men's and women's finals at the Perth Sevens, but both have improved their overall positions in the series.
The women were upset 19-14 by Ireland while the men were demolished 31-5 by series leaders Argentina, who were playing in a sixth straight final.
Both Australian teams were hoping to win on home soil for the first time since Sydney in 2018.
Despite the final defeats at a sold out HBF Park, Australia still had a productive weekend.
The women increased their lead at the top of the ladder from six to 12 points and the men moved up from sixth to third, just behind Fiji on points differential. But they are 14 points behind runaway leaders Argentina.
The women led 5-0 early but Ireland, who had lost 29 straight games to Australia, rallied to break a 14-14 deadlock. With a minute and a half to go, Eve Higgins burrowed over the line for the go ahead try.
Australia captain Charlotte Caslick scored the opening try but received a yellow card later in the half, continuing Australia's poor disciplinary record through the tournament.
Siblings Teagan and Maddison Levi were sent off, though the former was available for the final and contributed a try and two conversions.
Bienne Terita, who starred through the tournament, suffered a leg injury early in the 24-7 semi-final win over the United States earlier on Sunday.
"We have gone through a lot of adversity this weekend but super proud of this young bunch," Australian player Sharni Smale told Stan Sport.
Ireland, who had never won a series final, came into the tournament seventh out of the 12 teams.
Great Britain won the bronze medal with a 24-10 win over the United States.
In the men's final, Australia hardly threatened the Argentina line until Matthew Gonzalez crossed in the last few seconds.
"They just completely starved us of possession, it's tough to win when you don't have the footy," Australia captain Nick Malouf told Stan Sport.
It was still a commendable effort from the Australians, who lost two of their three pool games and only scraped into the quarter-finals as one of the best third-placed teams.
They scored a fine 22-7 semi-final win over Fiji, who finished fourth in the tournament after losing 24-7 to Ireland.
The final turned in the third minute when Australian Nathan Lawson was given a yellow card for a contentious deliberate knockdown call.
Argentina immediately exploited their numerical advantage just a few seconds later with Marcos Moneta racing 55 metres after taking a pass from a scrum as he notched his eighth try of the competition.
Argentina took just a minute of the second half to score their second try through German Schulz.
Matteo Graziano crossed twice and Moneta also chalked up a second try as the series leaders demonstrated why they are the top team in the competition.
