The Amicus trade union has called on the Government to accept a recommendation that the private health insurance firm BUPA should subsidise the VHI, its state-owned rival.
Reports this morning said the Health Insurance Authority was set to recommend that the Department of Health force BUPA to make regular payments to the VHI.
The authority reportedly believes the move is warranted for the purpose of "risk equalisation" because of the older and less profitable age profile of the state company's members.
At present, BUPA focuses its business on the more profitable younger age groups, while the VHI covers everybody and uses profits from the younger age groups to make up for losses incurred on behalf of older members.
BUPA has threatened to withdraw from the Irish market if it is forced to subsidise the VHI, but John Tierney of Amicus said the alternative would drive VHI premiums sky high.
"If we don't bring in risk equalisation, the cost of health insurance for anybody over 45 will probably go up to six or seven times what they're paying at the moment," he claimed.
"If we don't bring it in, most people won't be able to afford health cover in their old age."