A workplace dispute involving a former staff member of WA Deputy Premier Roger Cook will be investigated by the Western Australian Industrial Relations Commission, after the sacked employee claimed there was a "toxic culture" in the office.

Sanja Spasojevic worked for nine years in Mr Cook's electoral office in Kwinana, in Perth's south, before being sacked.

Mr Cook, who is also the Health and Mental Health Minister, said a number of workplace issues emerged relating to Ms Spasojevic during her employment and she was afforded procedural fairness at all times.

But in a statement, Ms Spasojevic claimed she was "afforded no explanation about my brutal and unexpected termination" and denied she was given procedural fairness.

She has taken her case to the Public Service Appeals Board, which is a part of the Industrial Relations Commission.

"I endured unbearable toxicity, discrimination, and inappropriate actions at my workplace," Ms Spasojevic alleged in a statement.

She said she tried to resign twice, in December 2017 and April 2019, and raised "serious grievances and concerns with the management and operations of the electorate and ministerial offices".

"It is a toxic work culture," she said.

"There is no recourse for staffers who try and speak out against wrongdoing and it is seen as disloyal behaviour and going against the [Labor] Party, which in my case is a huge organisation and currently the state government."

Health Minister rejects claims

Mr Cook directly addressed the claims at a press conference on Saturday and said his office had a "positive workplace culture" and one of "inclusiveness".

He said the workplace issues in question were put to Ms Spasojevic.

"Sanja was given the opportunity to account for these issues and ultimately was not able to provide an explanation to the satisfaction of her ultimate employer, the Department of Premier and Cabinet," Mr Cook said.

"These are obviously very saddening issues but ultimately the forum in which these issues should be addressed is the Industrial Relations Commission. And I understand that there will be hearings in relation to those [claims]."

Mr Cook would not comment on the details of the circumstances in which Ms Spasojevic left his office.

Ms Spasojevic said her sacking "broke my heart and affected my physical and mental wellbeing greatly".