Medibank has topped the list of health funds that have shed the greatest number of members, according to a new report.

The Private Health Insurance Ombudsman's latest State of the Health Funds Report shows that Medibank lost 45,676 customers between June 2015 and June 2016, followed by Westfund, which lost 865, and HCF, which said goodbye to 502.

The biggest winners from the exodus were HBF, which welcomed 49,949 new policyholders, Bupa, which won over 38,235, and NIB, which added 19,501.

The figures confirm Medibank had a tough 2016, with the Australian Competition and Consumer Commission accusing it of reducing coverage without notifying policyholders and an IT bungle that delayed the delivery of tax statements.