Jeni Mathieson, director of the 4Cs, the shire's only crisis accommodation service, said an increasing number of people - up to 50 a month - were turning to the service.

She said many people were looking for short-term accommodation while searching for longer-term options.

"We try and do what we can but there is just not the rentals available and there is a long waiting list for emergency housing.

"Our aim is to help where we can, to go that extra mile, but it's difficult."

Dianne Collis, property manager at Gerard Collins real estate in Pakenham, said most of the 250 properties they had listed were out of range for low-income families and pensioners.

"For a single mum with children, a two-bedroom unit is just not suitable.

"And larger properties, let for around $270 to $290 a week, are just not affordable."

Ms Collis said property openings could attract up to 30 people, but for many applicants, the rental prices asked were not financially viable.

"Rental demand has been high now for a couple of years. Once we had plenty of properties in the $220-$260 per week range but now there is hardly anything."

A quarterly state government report showed residential lettings in the 12 months to March 2009 fell 5.46per cent.

Shadow housing minister Wendy Lovell said low-income families were being squeezed out of the private rental market.

She said the March report showed that 80 per cent of private rental homes in Cardinia Shire were unaffordable for low-income families.

"The median rent for residential properties in south-eastern Melbourne increased by 1.8 per cent in the quarter and by 12 per cent than the same time last year," she said.

Centrelink statistics for 2009 show there are 6147 people in the federal electorate of McMillan receiving rental assistance and 4527 in La Trobe.

In June, there were 730 applications for Newstart allowance at the Pakenham Centrelink branch, a 5.3 per cent increase from May.