This week Auditor-General John Doyle refused to sign off on the final budget tally for 2013/14 financial year warning that an Education Department decision to write off seven out of every 10 public schools as partly "economically obsolete" was significantly reducing the government's school funding obligations.

The old school fete, with its lamington stalls and egg-and-spoon races, is no longer meeting school funding shortfalls.

Corporate sponsorship, auctions with holiday home stays as prizes, hired carnival rides, professional circus acts and gourmet food stalls are the new norm.

Last year, Westgarth primary school's The Whopping Great Fete took in $85,000. For this year's fate, on Sunday, the aim is to raise up to $100,000.

Westgarth assistant principal Lynne Mackie said the parent-run organising committee did  "the hard slog" and it was "a big commitment".

But with enrolments jumping from 400 to 600 in the past three years, fete earnings were spent on vital projects such as airconditioning for portables, upgrading playgrounds, and buying phys ed equipment.

The fete's volunteer chief organiser, Janine O'Connell, has for months been working on it seven days a week. With warm weather forecast for Sunday, she spent last weekend sourcing ice for the food stalls.

The mother of three says for her school's top auction prize this year, a new parent who is a real estate director donated a commission-free sale of a house, which is worth 2 per cent of the property value. The reserve price for the prize is $2000, but the agent reckons it's worth $18,000.

Westgarth fete's biggest earner is the stalls. More than 2000 plants will be on sale at $2 to $30 each and more than 1000 jars of jams and sauces, priced from $3 to $8.

Key attractions include the O'Sullivan & Benn Bicycle Emporium's circus activities, and its 25 eccentric bikes for kids to test ride.

Kathryn Fraser, an organiser of Princes Hill primary's November 16 Bazaar - also aiming to raise $100,000 - said it was "just a massive, massive thing to put together" but "being part of a community is putting your hand up and saying I want to help out in some shape or form".

Ms Fraser says: "We have essentially no money to maintain the school from the [government] budget, so a lot of it is keeping the facilities up to scratch, as well as being able to offer additional funding to specialist programs in areas such as art, Italian and sport."

Aside from the usual market and rides, talent quest and bands, the silent auction is expected to raise more than $10,000 and typically prizes are weekends away and vouchers for restaurant dinners. Several sponsors have paid $2500 each to have their name on banners and leaflets. 

Mother-of-three Melinda Wilson, the co-ordinator of the Clifton Hill primary school fair on November 22, is proud that her fair helped build the school's new $250,000 science building over three years.

Last year's $95,000 fete revenue was about $30,000 more than five years ago, but promotion now includes billboards, a website and a Facebook page.

The fair has 11 rides, a talent quest, band performances, 50 stalls, and the food profits - $25,000 last year - are boosted by parents' links to local eateries: Cavallini of Clifton Hill provides gelati and Jonathan's Butchers of Collingwood supplies meat for the barbecue.

Ms Wilson, who works part-time, says: "The fair is pretty much another [unpaid] part time job in itself." She is spending three hours a night on calls and emails. "It is a lot of work, but the school community does come together and the children love it."