Eleanor Bryant was a selfless speech pathologist. Her final act was to pull children from harm's way.

Eleanor Bryant went to work at a childcare centre northwest of Melbourne on Monday, just as any other day.

She was meant to make it home.

Instead, the 43-year-old died when a water tanker crashed through the fence at Macedon Ranges Montessori Preschool on Main Road, Riddells Creek about 2.20pm — just 40 minutes before the centre was due to close.

Police believe the truck hit a power pole before veering off the road and crashing into the kindergarten.

A three-year-old boy was taken to the Royal Children's Hospital with arm injuries, which police confirmed were non-life-threatening.

Eleanor, who was a speech pathologist and mother of an 11-year-old boy and nine-year-old girl, was trying to save children when she was struck, the Herald Sun reports.

Her devastated family said they would "miss her like crazy".

"She was the light of our lives: a cherished mother, wife, daughter and sister, and beloved by all her family and enormous network of friends," they said in a statement.

"Her infectious smile, sense of humour and passion for life made her a joy to be around.

"There is an enormous hole in our hearts today."

Watch: Carer killed and child hurt as truck crashes into kindergarten playground. Post continues below.

Friends and clients remembered her as a "truly remarkable lady".

"I will be forever grateful for everything she did for my daughter as her speech pathologist," one mum wrote online.

"This incredible woman has always been a hero to our family and now she is a hero to so many," another said.

Heartbroken community members have laid tributes at a growing floral memorial along the kindergarten's fence.

Nine's Today Show host Alex Cullen paid tribute to Eleanor on air, describing his childhood friend as "a light that lit up every room".

"It does not surprise me one bit that Eleanor pushed those school kids out of the way yesterday to ultimately save their lives. She always, always put others first and was a great example to all of us," he said.

Eleanor's local basketball club, where she worked as the equipment and uniform co-ordinator, said they were devastated by the loss of one of their own.

"Eleanor was the most kind, thoughtful and funny friend," they said.

Crash a "close call" for many children

Detective Senior Sergeant Christian Von Tunk said police believe the tanker veered off course on a bridge about 120m from the pre-school.

"That truck has lost control and has travelled through a fence and into the open playground area of a preschool where a number of children and teachers were situated," he told reporters on Monday.

"Unfortunately we've had one of the staff, a 43-year-old lady, struck by that truck, and she's deceased."

He said while "tragic" the outcome "could have been a lot worse", with extensive damage to play equipment where several staff and children were nearby.

"This is one of those close calls and I don't know how only one person has died today. It's unbelievable.

"I dare to say there'll be some kids getting squeezed very tightly tonight. That's a really rough one."

The truck driver was taken by ambulance to Royal Melbourne Hospital in a stable condition. He is assisting police with inquiries and is yet to be interviewed.

His employer, family-owned business McKenzie Water, said they were devastated following the crash.

"This is an incredibly distressing time, and our deepest sympathies go to those involved and their families and friends," owner Alana McKenzie said.

"Our experienced 68-year-old driver is understood to have suffered a medical episode and remains in hospital. We are doing what we can to support him and his family."

Police are yet to confirm whether the driver suffered a medical episode.

Victorian Member for Macedon Mary-Anne Thomas said it was a "tragic incident".

"My thoughts are with the staff, families, and community of the Macedon Ranges Montessori Preschool in Riddells Creek," she said.

"Thank you to our first responders and healthcare workers. I know our community will be hurting at this terrible time — please look out for one another.

"My thoughts are with the staff, families, and community of the Macedon Ranges Montessori Preschool in Riddells Creek."

Federal member for Menzies Keith Wolahan said Eleanor was a "hero who sacrificed her life to save children in her care".

"I hope her family finds comfort in her courage. May she rest in peace."

Victorian Health Minister and member for Macedon Mary-Anne Thomas thanked first responders who helped the injured.

"This is a terrible incident and our thoughts are with the family of the victims and the broader Riddells Creek community," she said.

The tragedy comes less than two weeks after 11-year-old Jack Davey was killed and four other students injured after an SUV crashed through a fence at Auburn South Primary School in Melbourne's east.

With AAP

Feature image: Supplied.