The father said he was "very, very devastated" at the loss of his "adorable" daughter.
The family was given the terrible news from police at around 10.30pm yesterday.
A close family member described the woman as being "really bubbly, really happy, a lovely girl".
"We are all devastated. It doesn't feel real," she said.
Police last night cordoned off a house at Kowhai Tce in the Christchurch suburb of St Martins.
A police spokesman confirmed that the address is linked to the Rakaia murder inquiry.
He refused to say why the house is of interest to investigators.
Jason Manuel, 47, who lives across the street says they are "good people, a normal family".
He came home about 7pm yesterday to police activity in the street.
"Police have staked it out all night. It's a bit odd."
Detective Inspector Darryl Sweeney said police officers and forensics experts are working around the clock at the Main Rakaia Rd scene to piece together "exactly what has happened".
The woman's body has now been removed from the scene.
The road is still closed.
"Police are grateful of the Rakaia community's patience and assistance as police go about their investigation," Mr Sweeney added.
"We appreciate the closing of the Main Rakaia Rd has caused some disruption, but would like to thank them for their understanding during this time."
The manager of the dairy farm where the woman's body was found was told by police the woman had been "missing for a little while".
The farmer, who only wanted to be known as Jori, knew about the fires in the area on Sunday night.
But it wasn't until he got up about midnight that he saw police outside his property.
"I went to have a look and they told me there was a body there, a lady who had been missing for a little while," he said.
"[The body] was right by the boundary fence, between the farm and the road.
"They said they were looking for two occupants of a 4WD who had been in the Rakaia river."
Local dairy farmer Michael Norton said thieves stole two 20 litre containers of petrol from his farm on Main Rakaia Rd on Saturday night.
He said they smashed the lock off shipping container and targeted the petrol, leaving behind tools, a water blaster and pump, of "more value than petrol".
Mr Norton noticed the break-in Sunday afternoon and reported it to police yesterday.
"I thought with all these fires and the body, and having petrol stolen like that, it seemed like a strange thing," he said.
"So I put two and two together, thinking there could be a link there. Obviously we don't know that for sure, but it made me a bit nervous."
A series of suspicious fires had been lit around 4pm in the Selwyn riverbed near State Highway 1, just north of Dunsandel.
It sparked a large emergency response, including four fire engines, 10 water tankers and three helicopters.
The Fire Service was first called to a fire at Selwyn river at 4.44pm.
When they arrived, they found two fires, one on either side.
"Obviously the guys were running around the river, lighting them," said Rakaia Volunteer Fire Brigade station officer Tyrone Burrowes, who was sure they fires had been started deliberately.
Two crews fought the fires, with assistance from a helicopter.
Later, at 7.37pm they were called to another scrub fire on Main Rakaia Rd.
The nearest unit was Kirwee Volunteer Fire Brigade.
As they were on their way, the member of the public, a "passer-by", rang back to give them a "heads up" that there was a body there.
Mr Burrowes wouldn't say whether the woman's body had been burned or was on fire.
He confirmed that Kirwee Volunteer Fire Brigade was first on the scene.
"They extinguished the grass fire and protected the scene for police," he said.
At 8.30pm, there were reports of yet another suspicious fire, this time at Overdale, south of Rakaia township.
A Rakaia ranker and Dunsandel fire crew responded.
Mr Burrowes believed that all of the fires were suspicious.
Police have been asking for sightings of a 4WD vehicle that was seen in the Selwyn River in the vicinity of the fires when they were first lit.
Anybody with any information in regard to suspicious vehicles or people in the area are asked to contact Christchurch Central Police Station on 03 363 7400 or Crimestoppers on 0800 555 111.
Locals are upset by the grisly find - the second such disturbing body discovery in the rural Selwyn district in the last three weeks.
The badly bashed body of Marcus Luke Tucker was found burned, dumped, and wrapped in some material on Drain Rd, Doyleston by Lake Ellesmere on Anzac Day.
Peter John Carroll, 51, of Bishopdale, Christchurch has been charged with his murder.
Three others have also been charged in connection with the case. All four are now before the courts.
