A major trade union says it will urge its members to opt out of Australia's electronic health record system unless its concerns are addressed.

The Electrical Trades Union has written to Health Minister Greg Hunt asking that the current provision in the My Health Record system allowing insurers and employers' doctors to view records be amended to automatically exclude access for workers compensation and for pre-employment reasons.

"The ETU will be informing its members that they should opt out immediately from the My Health Records scheme unless our concerns are met," union national secretary Allen Hicks said in a statement on Thursday.