Asbestos-related cancer claims against building-materials giant James Hardie have quashed assumptions that the flow of compensation cases would begin abating after hitting a "peak" last year.

James Hardie has unexpectedly faced a sustained increase in compensation claims from victims of the fatal asbestos-causer cancer, mesothelioma, prompting its actuaries to lift its liabilities by 12 per cent to $195 million.

Net sales grew about 7 per cent to $US2.05 billion, from $US1.92 billion a year ago. Credit:Bloomberg

James Hardie, which was involved in the manufacture and distribution of products containing asbestos until 1987, is required to pay 35 per cent of its free cash flow into a fund set up for asbestos victims.

A KPMG report for the company revealed there had been 392 mesothelioma claims reported in the 2018 financial year, a 5 per cent increase on the previous year and above its expectations by about the same amount. Asbestos experts say the bulk of compensation claims are coming from the "third wave" of asbestos victims.