Director general of health Dr Ashley Bloomfield has since clarified the contact was one of several people that came to drop off food to the women in a contactless way.
"One of them spent some time at some distance talking with the women, this can happen for example in our managed isolation facilities- people are able to communicate through the fence with others, there's a distance separating people."
Bloomfield said the Medical Officer of Health discussed the contact with the friend and there wasn't deemed to be any risk.
But he said the friend chose to self-isolate regardless and was tested for Covid-19 on Friday.
The swab was negative for the virus, Bloomfield confirmed.
He also told media today that one of the Covid-19 cases who has been isolating in the Hutt Valley has recovered.
A person is considered recovered from Covid-19 if it has been at least 10 days since the onset of symptoms, have been asymptomatic for at least 48 hours, and have returned a negative test.
The two sisters, one in her 30s and one in her 40s, arrived in New Zealand together on June 7 on a flight from the UK via Doha and Brisbane.
They were permitted on compassionate grounds to leave managed isolation to travel to Wellington via private vehicle, where they subsequently tested positive for Covid-19.
The women initially said they had not contacted anyone on their road-trip. But it was later revealed they came into contact with at least two friends who helped them after they became lost on the Auckland motorway.
More than 300 close contacts of the pair have been identified and tested, including other people in the Auckland hotel in which they had been isolating and other passengers and crew on their flight from Brisbane.
