Drewery said it would be a call-out that officers on the scene would never forget.
"I know the officers who have attended this scene will always remember it and will be reminded of it whenever they drive through or near the crash site."
Frost-Saywell had worked at Countdown Stratford since it first opened in 2015.
Countdown group manager Wayne Law said they were deeply saddened by this tragic loss of one their team.
"She was dearly loved by all the team, customers and the local community.
"Our focus right now is to support the family and our team in whatever way we can. "
Management had arranged for extra team members from other areas to work this week to support the store and there was a counsellor on site all week to assist colleagues.
Samantha Bailey met Frost-Saywell through the bar she worked at in Eltham and became firm friends with her. She said she was an "awesome, bubbly person".
"She was always cheerful."
Bailey said Frost-Saywell loved riding motorbikes and would often ride down to Whanganui to try and catch up with her when she lived there.
"She was one of a kind. She will be sorely missed."
Members on Facebook group 666 Moments also paid respect to their fellow member.
"R.I.P dear friend. Our condolences to her family and friends from all of us here," one wrote.
Another wrote: "Not the news I wanted to hear, I've known Frosty since we were in our early teens and I have a drink or 10 with her weekly, it's going to be quiet at the round table now girl."
Another friend was also "shattered". "She will be sadly missed. My visits to the Stratford Countdown won't be the same. RIP My Dear Friend."
The driver of the van remains in ICU.
Frost-Saywell died in the crash as emergency workers, passing motorists and nearby residents desperately battled the electrical fire that started under the bonnet of her car.
A neighbour said she was sitting outside her house when she heard a loud crash at about 7.55pm.
The car appeared to have been heading north towards Stratford and had crossed the centre line, smashing head-on into a van, the neighbour said.
Both vehicles ended up in the right-hand side of the south-bound passing lane.
Stratford deputy fire chief Kevan Old said one of the vehicles was on fire when they arrived and the police used seven extinguishers to try and get the fire out.
"It was electrical under the bonnet and it was very difficult to get out," Old said.
It took firefighters about 10 minutes to put the fire out and then they were able to remove the woman from the car quite easily, he said.
Old said in his 24 years in the fire service, it was only the second or third crash he had attended where a car had caught fire on impact.
"It doesn't happen often. We knew there were persons trapped before we left the station - it came up on my pager - so we actually geared up to deal with that."
The police serious crash unit is investigating.
