Medibank Private investors should brace for a hit to profits from slowing growth across the $20 billion industry, and extra investment the health insurance giant needs to fix its customers relationships, chief executive Craig Drummond has warned.

After a two-year period in which investors benefited from a sharp focus on improving profitability – a much needed strategy to ensure the privatisation, which reaped $5.9 billion in November 2014, was successful for the government – Mr Drummond said Medibank now needed to address failing its customers in many respects.