Dixie Marshall has stepped aside from day-to-day media management and will take on a new strategic communications role in the Barnett Government.
Ms Marshall will work four days a week in her new role as strategic communications director, focusing on government advertising, marketing and digital.
Rachel Donkin, previously a media advisor to Premier Colin Barnett, has been promoted to principal media advisor.
She will have final sign off on the Government's communications with journalists.
Danielle Benda, another media advisor in the Premier's office, becomes senior media manager and will take on responsibility for staffing in the 21-strong ministerial media team.
It is understood Ms Marshall will take a pay cut in line with her four-day-a-week workload, with some of the savings redirected to higher salaries for Ms Donkin and Ms Benda.
A Government spokeswoman said: "The separation of media and digital/paid communications reflects the changing media landscape. This is a smarter and more streamlined focus of roles.
"Details of staff salary levels will be contained in the next updated Ministerial Resourcing Report, to be tabled in Parliament in due course.
"There is no additional net cost to the taxpayer under these changes."