A landmark national study of 5000 international students has found more than half lived in poor conditions, including overcrowded or unsafe accommodation, and many experienced sudden rent increases and overcharging.

Researchers from the University of NSW and the University of Technology Sydney discovered students had been exploited in share housing that they had found on social media and websites.

International student Mayane Dore had difficulty recovering her bond.

Half of all respondents said they had experienced one or more problems including being deceived about the accommodation they received, landlords moving in extra people without the consent of tenants and overcharging. Students also reported living in overcrowded accommodation and being unable to recover their bond.

Mayane Dore, a PhD student at Macquarie University, lived with four others including her boyfriend in Randwick for two months until early this year.