Labor's Darling Range candidate Colleen Yates has come under intense scrutiny over an online resume as she seeks to replace Barry Urban in a byelection triggered by his resignation.

Fresh doubts have emerged over the educational background of Labor's Darling Range candidate after two universities in the United States contradicted claims she made in an online resume.

Colleen Yates listed degrees from Washington University in St Louis in her LinkedIn profile and said she had studied at Fort Lewis College and the University of Phoenix.

But Washington University said it did not grant Ms Yates a degree and Fort Lewis College had no record of her ever enrolling at the university.

The new revelations came after Labor was forced to defend Ms Yates for listing an MBA from the University of Western Australia on her now-deleted LinkedIn profile despite never attaining the degree.