Wellington students say flats are being snapped up before they even get the chance to apply for them.

Data from Trade Me Property shows there's been a 70 per cent drop in supply of rentals from last January.

Victoria University student Lizzie Addis said she's just signed for a flat in Hataitai but it's been an awful few weeks battling hundreds of groups for a place to live.

"You'd email enquiring about a place and they just wouldn't get back to and they wouldn't offer you a viewing and the next thing you hear from them is that the place had been rented already," she said.

"I hadn't even had a chance to look at it, or even apply for it and they'd already rejected you from the get go."

The Trade Me Property data shows median rent prices have reached a record high of $480 a week.

"They'd be asking crazy amounts of money to live in a place that was either ages away from uni or had so many things wrong with it that's affecting your health," Ms Addis said.

"We saw places that were mouldy and damp and they were asking for almost $800 a week for a four bedroom place."

New Zealand Union of Students' Associations spokesman Rory Lenihan-Ikin said there's not much they can do to help.

"We give students advice about turning up to flats with their references, with their CVs, their application filled in and the ability to make a decision on the spot to get the best chance."

Mr Lenihan-Ikin said the impact of Kaikoura's earthquake, which also caused significant damage in Wellington, hasn't helped.

He said it's left several apartment buildings out of action, tightening the squeeze on supply.