THE "cherry picking" of younger healthier subscribers by health insurance companies was opposed by Mr Padraig Flynn.
The EU Commissioner for Social Affairs was addressing the AIM conference in Dublin. The meeting discussed increasing health costs and how to pay for them.
"It is evident that if `cherry picking' is permitted, solidarity will suffer," Mr Flynn said.
"What is clearly needed is a system which caters both to the need to maintain solidarity while ensuring that competition is not unnecessarily stifled."
As part of defending the principle of maintaining solidarity he said, the Commission had recently agreed on a proposed amendment to the Treaty which would include reference to the promotion of services "of general interest".
He acknowledged that it was not guaranteed that all memberstates would accept this, or that in itself it would lead to any special change.
But he said it showed that he and his colleagues understood that services "of general interest" occupied a special place in Europe.
Mr Flynn urged the conference to "forcefully drive home the message that your organisations are essential to Europe's continued well being and to continued social solidarity in particular.
"I firmly believe that it is essential that the European model of social protection is preserved for future generations."
There was no evidence that high levels of social protection and a tradition of social consensus caused high unemployment in Europe. "Within the EU, countries with low levels of social spending are not more competitive than those with high levels - indeed, the opposite is the case, he said.
A Commission report on social protection last year had had an overwhelming response, including from AIM members, and this would provide momentum for the future, he said.
One way of ensuring that Europe could finance its future was through increasing employment, thereby reducing social welfare payments and increasing revenues.
While the demands of long term care for an ageing population represented a challenge, it was not an insurmountable one. It could be met in a variety of ways, including a combination of state and individual provision, he said.