For the first time in over a decade, Homeseeka had no available rentals for about a week, according to property manager John Warren.
He said the rental market was extremely competitive, with the vacancy rate low across the south-west.
"As soon as you put a three bedroom property up you get up to 10 inquiries in about the first 24 hours," Mr Warren said. "For July that's pretty high."
Mr Warren said the high demand for rental properties had driven the prices up by $20 to $30 a week in the past two or three years.
He said Warrnambool was becoming an increasingly popular place to live.
Mr Warren said interest in properties on the fringe of Warrnambool had also grown in the past 12 months.
The median price for a rental in Warrnambool is $360 a week compared to $335 for regional Victoria.
The Standard reported in January open for inspections were attracting dozens of people.