Woolworths has come out on top of rivals Coles and Aldi with the best supermarket discounts this week, a new research project has revealed.

The folks over at One Big Switch have dived into the grocery catalogues and found the best supermarket deals on everything from milk to apples.

Woolies has deals on yoghurt, Oreo cookies and coffee that have given it the edge on its competition, One Big Switch’s Joel Gibson said.

“If you want to save the most on groceries you need to look at the catalogues every week … but no one has the time to do that,” he said.

“That’s where we come in – we’re giving you a starting point when you make a shopping list every week.”

The research is based on prices quoted in Sydney so actual discounts may vary across the country, but Mr Gibson said it pays to shop around regardless of where your supermarkets are.

“The best strategy is to pick the eyes out of the specials and everyday low prices at all three supermarkets,” Mr Gibson said.

“The evidence is there that it pays to be disloyal … one supermarket will do a 50 per cent off special one week and another does it [the] next week.”

The highlights at Woolworths this week are half-priced 33L eskies at $26 and mangoes for $2.90 each.

Coles came out ahead on mushrooms, muffins and broccoli.

The chain is now advertising 42 Fairy dishwasher tabs for just $18.50.

Aldi has fewer promotions than its rivals but has low prices on tea bags, bread and apples.

The German giant is selling a 15-taco kit with 500g of Mexican beef and beans for $15 this week.

One Big Switch has not listed every special or 50 per cent discount but has instead focused on the best deals available this week.

To decide which specials were better, Mr Gibson combined unit prices with the practicality of packaging size, popularity and seasonality.

Both discounts and everyday low price items were included in the list.