Staying put and settling for the apartment they live in - rather than searching for one they'd prefer that would meet changing lifestyle needs - has become the only option for many tenants.

However, the upside is that the long-term tenant is not only cushioned from the flat-hunting fray, but is often paying far less rent than current market rates.

Louise Costelloe is one of a growing number who cannot aspire to move to a nicer place due to the chronic shortage of accommodation.

Unable to find a larger, more affordable apartment to share with her boyfriend, she has opted to hold on to the studio flat in Ranelagh where she has lived for five years. She pays £60 (€76.20) a week in rent and says the most she could stretch to for a new apartment would be £100 (€127) a week.

At one point she and her boyfriend found a two-bedroom apartment in Monkstown, but it fell through when the occupant "couldn't find another flat and decided to stay.

"I'd obviously like to move somewhere bigger but I'd also like to stay in Ranelagh. I've been here for five years and have friends and family nearby and the pub we socialise in is here. It is a lovely area, it has everything and you don't have to get a taxi home at night. I'd much rather be here than out in the middle of a housing estate."

Ann Marie Bohan pays £230 (€292) a month for her room in a three-bedroom basement apartment in a converted period house in Phibsborough, where she has lived for over four years. As with Louise Costelloe, the convenience of this location has influenced her decision to stay put.

"I would like to buy a place, but as location is very important, it is impossible at the moment. It is also quite difficult to save enough for a deposit if you are paying rent at the same time. I really have an ideal location at the moment which is very close to the city centre and also to most of my family and friends."

Bohan, who is self-employed and works from home, says: "I need to be able to nip out and meet people for lunch or a quick coffee to save my sanity; I can't do that if I am living in a house up in Drogheda."

Another reason for staying put is that Bohan feels her landlord is decent - if there are any problems he sorts them out fairly quickly. She and her boyfriend Donall would like to get a place together but "his rent is even less than mine, so we would more than likely end up paying double what we are currently paying, even for a one-bedroom apartment.

"Also, he happens to just live around the corner from me; the situation is not as critical as it would be if we were living at opposite ends of the city from each other."

According to Deirdre Brosnan of Lisney, those who flat-hunt do so because "in the vast majority of cases, people are looking for a new property to rent because the owner is either selling or moving into the house/ apartment themselves".

Moving house or apartment often involves increased expenses, Brosnan says, as the open market price may well be higher than an average rent increase after one year of occupancy.

However, landlords will often keep rental increases to a minimum rather than lose good tenants, according to Carina Warner of Hooke & McDonald's letting department.

But this is not always the case. If the apartment is in a prime location such as the IFSC or Temple Bar, a landlord may want to command the market rent - regardless of whether it's beyond current tenants' means.

"Generally, rent reviews would be high in prime locations, particularly if there is a good standard of finish and they have spent a lot of money on it," Warner says. "These kinds of apartments would generally have a lot of re-lets."

While city centre apartments are an increasingly scarce commodity, those who do vacate are often returning to their home countries where the cost of living is more reasonable.

"Quite a few left the country at Christmas when their work contracts were finished," Warner says. "It is now over £700 (€889) for a one-bedroom apartment, which is quite steep.

"Many of them opted to return home to England or parts of Europe where the cost of living is cheaper. Some would have finished out their lease or taken advantage of a six-month break clause in the lease."

But even given this exodus, the numbers of those clinging to their apartments has increased and there is a lack of new stock coming on stream, due to Government anti-investor measures.

"When an apartment goes on show, we have at least a dozen people queuing to see it. The situation is getting worse."

emorgan@irish-times.ie