The mining boom made WA's wealthiest people richer but left the State's poorest well behind, a study has revealed.
Compiled by Curtin University, the report into the boom and its impact on wealth across WA found the State overall made substantial financial gains.
Regional areas such as the Pilbara and Gascoyne became the richest in Australia because of the boom, while household net wealth in WA rose 70 per cent, or almost $270 billion.
But most of those gains flowed to 20 per cent of the State's richest people, who accrued about 65 per cent of that rise.
The study found the top 20 per cent has an average household wealth level of $2.5 million.
Combined, they hold 62 per cent of the State's total wealth.
The bottom fifth of the population have less than one per cent of the State's wealth.
At the start of the boom the richest 10 per cent of households had about 3.8 times that of the poorest 10 per cent. By 2011, this had reached 4.5 times.
Curtin Economics Centre director Alan Duncan said while most households had benefited from the boom, the gap between rich and poor had grown between 2003 and 2011.
"The boom has benefited the majority of WA households, with rising employment opportunities and substantial increases in real incomes and household net wealth," he said.
"But income growth across the boom period has created a greater gap between high and low- income households, both in terms of income and wealth."
Among the biggest winners from the boom have been tradespeople. Households headed by a tradie account for about a fifth of the richest 20 per cent.
The study found West Australians reduced their holdings of shares, instead sinking their money into property.
The dive into property meant almost 60 per cent of all high- income earners have a mortgage, compared with 53 per cent elsewhere in Australia.