Complaints about private health insurance rule changes doubled in the September quarter, coinciding with "upheaval" in the sector as funds roll out the federal government's new classification system by the April 2020 deadline.

The Private Health Insurance Ombudsman received a total of 1029 complaints in the September quarter, up 2 per cent on the previous three months and flat on the September 2018 quarter. Of these, there were 56 complaints about insurer rule changes, up from 27 in the previous quarter.

Complaints about health insurer rule changes have increased. Credit:Mario Borg

While the ombudsman did not break down the "rule change" complaints category, Grattan Institute health economist Stephen Duckett said the significant "upheaval" as funds rushed to comply with the new classification system "might account for the rise in complaints about eligibility and rules".

Under the reforms that began in April, insurers were given 12 months to reclassify all their hospital policies as Gold, Silver, Bronze or Basic and meet minimum requirements for each tier. The aim is to make it easier for consumers to understand inclusions for different levels of cover and compare offers between insurers. Pregnancy and birth, for example, must be covered in the top Gold band and will be covered by some, but not all, Silver-plus policies.