High power prices and heating restrictions imposed on homestay students are driving people to the library on cold winter days - to sleep.

Language school students Justina Liu and Dory Wang, who were seen napping at the New Lynn War Memorial Library last Saturday, say they go there if they want an afternoon nap, because their homestay parents won't let them use heaters at home during the day.

"It's nice and warm here, and the seats are really comfortable," said Miss Liu, who is from Hebei, China.

"Of course the best thing about it is that it's free and there's no one telling you to turn off the heater."

But it's not only homestay students needing a warm place to sleep.

Housewife Jan Togiola also said she went to "libraries with plush seats" to catch a nap in between reading the newspapers because high power prices had made it "impossible to afford" heating in her home.

Library user Catherine Jones said she found such behaviour "rude and inconsiderate" and had complained to staff at the Auckland Central library a couple of times in the past fortnight.

"It's not just the sleeping ... sometimes it's the snoring that I find irritating when you want to have a quiet read in the library," Mrs Jones said.

"It's just rude and inconsiderate for people to be treating our public libraries like some cheap motel."

An Auckland City Libraries spokeswoman said people had probably been sleeping in libraries inadvertently since public libraries began.

"It is heartening to hear that people see our facilities as warm and welcoming places to relax and read at the same time," said Allison Dobbie, Auckland Council's libraries and information manager. "We haven't seen any noticeable increase in people napping ... and we do have a security guard who can assist customers to find a seat by moving along customers who are sleeping or taking up more space than required."

She said the libraries had rules of behaviour that required customers to "behave in a way that is not disruptive or interferes with other users' enjoyment".

"If that happens, talk to one of our staff for assistance," Ms Dobbie said.

"If customers are identified as using the library to sleep on a regular basis, we advise them that the library is too busy a place for that behaviour and ask them to move along."

Following the creation of the Super City in November, library users now have access to books from all public libraries in the Auckland region, which has resulted in an increase in membership and borrowing.

"Libraries have become much busier places, which does mean that sometimes it can be hard to find a place to sit," said Ms Dobbie.

"They are no longer just places people come to read and study, but where friends connect and travellers come to check emails or find out information about the region."