Representatives of the Fairfax County employes' retirement system told the county Board of Supervisors this week that the county retirement fund is financially sound now but could face problems in the future.

Edgar R. Poole, of the Uniformed Retirement System, told the supervisors the county may have to increase its financial support of retirement programs to 10.7 percent in fiscal 1981 to forestall major financial probelms in three years.

The county contributes 9 percent of its annual payroll of nearly $100 million to four separate retirement systems.

Poole and six other representatives agreed to meet with county staff members to draw up specific recommendations on the matter.

Poole also told the supervisors that some employes are facing problems while applying for retirement funds. There are times when former employes can collect disability pay under the county system but are blocked by state law, he said.

Retirees trying to collect 100 percent disability for heart and lung diseases face some problems trying to prove total disability, Poole said.

"There is no problem when someone falls off a ladder and hurts his back but there is when it comes to heart and lung problems," he said.

In a related matter, a former member of the Fairfax County Employe Advisory Council told the supervisors the county ranks third behind Arlington County contributes 15 percent of its general retirement fund, compared with 12.5 percent in Montgomery County and 7.1 percent in Fairfax. Retired Fairfax employes also get less in benefits than retired workers in Arlington and Montgomery counties, Yeatman said.