Research has found significant sexism and discrimination within Australia's largest defence companies.

A new report by Canberra-based consultancy Rapid Context has gone through Australia’s 20 largest military firms, and found just one in five workers are women.

The national workplace average is around half.

Additionally, just over one in seven defence sector managers are women, compared to the national average of about a third.

Women were also found to be leaving defence industry jobs at disproportionately high rates compared to male counterparts.

The research said the high turnover is related to sexism, sexual harassment and gender bias.

The Federal Government will spend over $200 billion dollars on its defence capability over the next 10 years, meaning the industry will “need a renewed focus on attracting and retaining highly skilled staff”, according to the report.

“Failure to identify and address the reasons women leave the defence industry puts at risk the industry's ability to take advantage of growth opportunities and deliver Australia's defence capability,” it concludes.

The report is accessible here.