The price of a bag of coal is going up by €1.20 today, with a bale of briquettes costing 24 cent more.
The price rises are the result of the implementation of the second phase of the Solid Fuel Carbon Tax.
Recent Census information shows that more than 200,000 people in Ireland rely on either coal or peat to heat their home.
The tax applies to kerosene, marked gas oil, liquid petroleum gas, fuel oil, natural gas and solid fuels.
A spokesperson for Age Action Ireland has urged the Government to ring-fence money collected through carbon taxes to protect the most vulnerable people.
Speaking on RTÉ's Today With Seán O'Rourke, Eamon Timmins said the impact of price rises in coal and briquettes due to the solid fuel carbon tax would be considerable.
Mr Timmins said older people were "at the pin of their collar" from the multiple new taxes and charges coming out of a fixed State pension.
He said people were dying of cold-related illnesses because they could not afford to heat their homes to a safe level.
He said the money brought in through carbon tax should be ring-fenced and put into the means-tested winter fuel allowance.