Unleaded petrol costs have risen 5.6 per cent since this time last year, but hidden costs are the main culprits responsible for pumping up motoring budgets, the survey found.
The RACV 2007 Vehicle Operating Costs survey said hidden costs such as servicing, insurance and loan interest rates on average rose up to 7 per cent compared to last year's survey.
At the same time, depreciation figures show vehicles' value falling faster.
After examining the 37 top-selling vehicles across 10 categories, the survey found the cheapest car to own and run was the Hyundai Getz at $116.54 a week.
This was $5.34 more than last year's cheapest vehicle, the Kia Rio.
The most expensive was still the Toyota Landcruiser GXL turbo-diesel, at $357.51.
The Mitsubishi 380 ES was the most affordable family car at $200.44 a week, a weekly increase of $4.46.
Meanwhile, lower price and service costs helped Ford Falcon outperform its rival Holden Commodore, costing $229.13 a week compared with $233.40.
RACV Chief Engineer of vehicles Michael Case said the Federal Government's $1000 grant to LPG car purchases helped ease the overall running costs of these models.
Although eight vehicles across the 10 categories managed to retain last year's rank as cheapest in their class, there were still some significant cost increases.
For example, the Kia Carnival rose 14.7 per cent to $216.68, while the Honda CR-V cost $203.86 a week, a 7.4 per cent jump from last year's survey results.
Mr Case said the survey showed the cost benefits of diesel and hybrid vehicles, which more motorists were considering investing in as fuel prices continued to skyrocket.
"A diesel Volkswagen Golf will save you around $2.95 a week - nearly $770 over five years," he said."
"That's also a saving of around 11kg of greenhouse gas each week," he said.
"The Honda Civic hybrid meanwhile, provides a fuel saving of $9.46 a week and can save 17.9kg of greenhouse emissions."
The survey data was collected in March and April.
RACV calculations are over a five-year ownership period and are based on the average operating conditions for the private motorist, including travel of 15,000 km a year.