The WA Government is to increase compensation to families after workplace fatalities.

A planned amendment to the Workers Compensation and Injury Management Act will increase the sum paid to dependants to $554,727, indexed annually, from $304,185.

The weekly allowance paid to support each child will rise to $133 from $58.10, while outdated definitions will be removed to ensure equality of compensation access for de facto partners.

The amendments will also simplify the method for dividing funds between multiple dependants, and streamline the claims process.

The new lump sum is 2.5 times the maximum compensation payable for non-fatal injuries.