FATHER and son farmers have been killed in a freak work accident in country Victoria.

The Herald-Sun reports John and Michael Helyar were using a front-end loader to carry a windmill at their property near Rainbow, 350km north-west of Melbourne.

But the windmill became unbalanced and toppled, contacting overhead power lines just before noon.

An Ambulance Victoria spokeswoman said the Helyars died instantly.

A man who rushed to help suffered a shock and another who tried to drag him free was also shocked.

The injured pair, aged 65 and 35, were transported to Melbourne by air ambulance and remain in the Alfred Hospital in a serious condition with burns.

Rainbow locals said the Helyars were community stalwarts.

Michael Helyar, a father of two, was the president of the Jeparit-Rainbow Football Club in the Mallee Football League.

He had played with the club for many years before succumbing to a shoulder injury.

His father was heavily involved with the local golf club and was from one of the district's traditional farming families.

"It's very, very tragic,'' a local said.

"The Helyar family is an old family in this district. They're well respected members of the community. It's absolutely devastating.''

Ambulance Victoria intensive care paramedic Jason Hunter said the survivors had suffered severe "exit wounds'' to their feet where the electricity left their bodies.

He said they were conscious throughout the flight but required substantial pain relief and were placed on drips to replace fluids lost through the burns.

"I'm sure they'll be in hospital for quite some time yet,'' Mr Hunter said.

WorkSafe spokesman Michael Birt said four investigators had travelled to the farm to launch their inquiry.

Mr Birt said it had been a horror start to the year for workers with 11 workplace deaths - up two on last year.

"Most of those have occurred in regional Victoria,'' he said.

Of the 11 deaths, four have occurred this month with three in the past week - all in country Victoria.

"We've had four electrocutions in the past 12 months despite the look up and live campaign which has been going around for decades,'' Mr Birt said.