The 68-year-old was located deceased in a bed at his home in Barkly Street at around 4.30pm on Sunday.

Police suspect the man had been using a carbon monoxide emitting outdoor gas heater in his bedroom to keep warm.

Ararat police sergeant Shane Allgood said the death was particularly sad given it could have been prevented.

"It appears to be the case that a reasonably healthy person has died unnecessarily," he said.

Sgt Allgood said a neighbour raised the alarm after they became concerned for the man's welfare.

"The neighbour has removed a gas bottle from the room, which had an outdoor radiant heater attached to it," he said.

"Inspection of the house found the main heater in the lounge room wasn't working.

“We suspect the man has been using the outdoor radiant heater to keep warm and the toxic fumes from that have killed him."

Sgt Allgood said the most likely cause of death was from carbon monoxide poisoning.

"We have been able to find the packaging of the item used and it clearly states that it is not to be used inside," he said.

"We reiterate that LPG (Liquid Petroleum Gas) devices are not designed to be used inside premises.

"It is important that family, friends and neighbours check on each other, especially the elderly or people who live alone, to ensure that this isn't occurring.

“If it is, then you need to take steps to have them stop doing it.

"This was a particularly old house with very high ceilings.

“If someone has still died in those circumstances that means it could happen a lot quicker in houses built these days which are air-tight and have lower ceilings."

Country Fire Authority District 16 Operations Manager, Bernie Fradd said under no circumstances should people ever use LPG cylinders inside.

Mr Fradd said residents should also ensure their indoor heaters are serviced on a regular basis.

"As the cold weather continues it's important to ensure indoor heaters are still in a safe, working condition," he said.

"They should be serviced regularly, at least every two years, to help detect faults.

"CFA is also warning people to never use heaters and cookers which use LPG cylinders inside.

"Carbon monoxide is a known silent killer as it can't be seen and has no odour.

"Simple steps can help prevent a potentially tragic outcome."

Dubbed the 'silent killer' carbon monoxide is found in fumes produced any time you burn fuel in cars or trucks, small engines, stoves, lanterns, grills, fireplaces, gas ranges, or furnaces.

It can leak undetected from faulty, unserviced heaters and can be lethal as it can't be seen and has no smell.

A new television and cinema campaign called 'Cold Feet' has shown that carbon monoxide poisoning can happen in any home or building with gas heating appliances, including newer ones.

Energy and Resources Minister Lily D’Ambrosio said householders need to take the messages contained in the safety campaign seriously. 

“There is no room for complacency when it comes to carbon monoxide poisoning – it poses a real risk in every household,” she said.

“To minimise the risk of carbon monoxide poisoning in your home, find a gasfitter in your local area and make it a habit to get your gas heater serviced at least every two years.”

Authorities recommend having your heating system, water heater, and any other gas, oil, or coal burning appliances serviced by a qualified technician.

Never use portable flame-less chemical heaters indoors and seek medical attention if you are feeling dizzy, light-headed, or nauseous - all symptoms of carbon monoxide poisoning.