Given the teams are able to drop their worst result later in the regatta, the disqualification is not terminal to Aleh and Powrie's medal chances, but it places them under pressure to deliver consistently strong results from here on in.
The Japanese pairing of Ai Kondo Yoshida and Miho Yoshioka are the surprise leaders after day one, with their first and fourth placings putting them three points ahead of the Slovakian crew of Tina Mrak and Veronika Macarol, who have moved into second.
Aleh and Powrie, perhaps the forgotten gold medalists from 2012, are seeking to become the first Kiwi sailors to win back to back gold.
The men's 470 crew of Daniel Willcox and Paul Snow-Hansen are also among the leaders after a strong opening day.
The pair, who are competing in their first Olympic regatta together, are in third position overall after kicking their regatta off with a second and 10th placing.
Croatians Sime Fantela and Igor Marenic lead the fleet with a handy six point advantage over the Australian pairing of Mathew Belcher and Will Ryan.
Snow-Hansen and then crewmate Jason Saunders, who has made the switch to the Nacra 17 class, finished fifth in the same event in London four years ago.
In the Laser class, Sam Meech has slipped back to seventh overall after struggling in the later races today.
Sitting in third place after the opening day, Meech opened day two with a sixth place, but followed up with a 14th and 17th placing. The Laser fleet has a rest day tomorrow, with just four races remaining before the top 10 ranked sailors take part in the medal race.
In the Nacra 17, Gemma Jones and Saunders are in 13th position after two races sailed on day one.
Josh Junior had another disappointing day on the water, slumping to 20th place overall to be well out of medal contention in the Finn class.
After a disastrous opening day, where picking up an 18th and a UNF, Junior needed two top five results to get himself back in the medal hunt, but the 26-year-old could only manage a best finish of 14th in his two races.
