Mr Vai said his friend and neighbour Paul Kautoke had sent him a text message while he was working to tell him that there had been a fire at one of their group of Housing New Zealand flats.
"I asked him whether my house was all good ... he said it had been a big one.
"It's just a shock to everyone around here."
Mr Vai described Ana as a "girly girl" who always wore a dress and a smile.
Mr Vai's mother Lupe said she was was cooking in her home after 4pm when her daughter ran inside telling her she smelled smoke.
"I said it must be a barbecue and then she ran outside [into] our backyard and then she said 'mum, the next-door neighbour's house is on fire'.
"I was talking to the mum and the mum was saying that she didn't know that one of the daughters were sleeping upstairs. She was downstairs with the kids and half of the kids were outside playing."
Ana was a "beautiful little girl" who would often play in the area outside her home, Mrs Vai said.
Paul Kautoke, 27, said he grabbed a garden house and connected it outside the house but it wasn't long enough to make it to the second floor of the house where the fire was based.
He said he tried to go upstairs to rescue Ana but the smoke was too thick and he was forced back.
"It was just black. We tried to turn the lights on, but the lights wouldn't work."
Mr Kautoke had to be treated for smoke inhalation afterwards.
"I didn't do anything ... I didn't do enough."
Ana's mother tried to rescue her, Ana's aunty, One Kaho, told One News.
"She tried to get out but the smoke was so thick, and the fire brigade got there about the same time and got them away, but they got to Ana too late.
"Anyone in the family will tell you how cheeky she is, how she can walk into a room and own it, even as a 6-year-old. She loved performing," Ms Kaho said.
Senior fire investigator Mike McEnaney said a smoke alarm went off when the fire started.
"A young 12-year-old boy was able to go upstairs, get a young child out of one of the bedrooms where the fire was [and] bring him out, which saved his life.
"Unfortunately he wasn't aware that there was a sister in another room asleep."
The Fire Service were called by the boy and arrived within four minutes of being called, Mr McEnaney said.
"The girl was still up in her room and firefighters made an immediate search of that room, found her immediately and brought her straight out.
She could not be revived.
"It's devastating when children are involved with fire and the end result is that somebody passes away - it's really tough for everybody and extremely hard on the family."
National fire investigation manager Peter Wilding said just under 200 fires in the past five years had been started by children under the age of 5 - usually by playing with matches or lighters.
