Lulu Cathro has been living on campus at an ANU residential college since her first year of university.

Now in her third year of a science degree, it's time for her to clear out and make way for incoming first-year students.

But with thousands of other students in the same boat, Ms Cathro and peers Ben McCarthy and Joe Coultan are finding it impossible to successfully secure rental accommodation for the new year.

Typically at the ANU students in residential colleges move out at the end of their third year to make way for incoming students.

"It's a general expectation that we'll move out after that time," Ms Cathro said.

Students are searching for accommodation for the new year to make way for a new wave of students. ( ABC Radio Canberra: Hannah Walmsley )

ANU offers an accommodation guarantee to undergraduate students who meet a specific criteria.

The guarantee caters for incoming first-year students as well as Indigenous students, Tuckwell scholars, medical students, exchange and transferring students and students with a disability.

"With more and more people coming to the ANU, and the colleges needing to make way for the first years, it's just getting more and more competitive," Ms Cathro said.

"So there's a huge wave of students looking for somewhere to live."

Ms Cathro and her peers have been searching and applying for rental accommodation without success.

"We've been applying and getting knocked back for the past two-and-a-half months," she said.

"But everyone is in the same boat.

"We've put in so many applications and can't get anything anywhere near uni.

"We started by looking at places as close to uni as we could, but very quickly we realised how competitive it is, so now we're looking further and further out."

The latest census figures revealed almost 30 per cent of Canberrans rented their place of residence.

Tenants' Union ACT executive Deborah Pippen said Canberra had the third highest median weekly rent of all the capital cities.

"We just don't have enough supply," she said.

"There's also a lot of stigma attached to different groups within the community and they're the ones who are going to find it harder to find somewhere to rent."

Negative perceptions

And while the students are putting their best foot forward with each application, Ms Cathro said she found it impossible to compete with professionals and families.

"We've even been offering upwards of $80 on top of what the owners are asking for; we don't have pets, we don't smoke and we all enjoy gardening.

"But people do seem to have a negative view of students.

"When we go to an inspection we dress well and we take references, but when there are young families there we know we haven't got a chance."