"I am very pleased to appoint Ms Dew," said State Services Commissioner Peter Hughes.
"She is highly regarded, has a reputation for integrity and a thorough understanding of New Zealand employment law," he said in a statement.
Dew is also leading a review into the culture of the New Zealand women's hockey team.
Newsroom reported claims that more than a dozen former staff at the Commission for Financial Capability had raised concerns about a bullying culture and mismanagement led by Maxwell.
SSC will report to Commerce and Consumer Affairs Minister Kris Faafoi on its findings early next year.
The SSC's move comes as National MP Maggie Barry has also been accused of bullying staff.
The Weekend Herald revealed Barry had been twice investigated over bullying claims this year – including accusations she expected staff to do political party work on taxpayer time, which would be unlawful.
Barry has said the allegations were investigated and she was cleared by the Parliamentary Service.
Speaker of the House Trevor Mallard has also launched an independent review into bullying and harassment at Parliament.
While the review had been planned for some time, it has been given renewed impetus following the sexual assault scandal surrounding law firm Russell McVeagh, and allegations of bullying behaviour against Botany MP Jami-Lee Ross.
It has also been reported that a third of staff in the Department of the Prime Minister and Cabinet have either seen cases of bullying or have been bullied themselves.
Hughes told media this morning that the public service, like most workplaces, "probably can do better" when it comes to tackling bullying.
"But I've seen nothing to suggest that is a systemic problem across the public service," he said.