A can of pre-mixed bourbon costs the same as a soft drink in many parts of south Auckland.

In total Manukau City has 502 liquor licences for a population of nearly 329,000 people _ one for every 655 people. Of the total amount, 185 are off-licences, where alcohol can be taken off the premises.

Many of the independently owned shops are found together along main arterial routes, at shopping centres, near schools, bus-stops or sitting beside corner dairies, with bars and clubs not far away.

In the wake of liquor store owner Navtej Singh's murder, Prime Minister Helen Clark said the availability of alcohol and the role of consumption were key drivers of crime in south Auckland.

But per head the city doesn't have the most liquor licences in the country. Christchurch which has a similar sized population has one licence for every 331 people.

However, Manukau liquor licensing inspector Paul Radich says it's not the total number of licences that's a problem _ it's the fact that a "high proportion" _ 36.7 per cent _ are off licences, and that bars, dairies, supermarkets and bottle-shops tend to be "clustered" tightly together.

Cheap alcohol is the result of competition. Pour that into one of the most socio-economically deprived areas in the country and it's been a cocktail for trouble, community leaders say.

A Weekend Herald investigation has found retailers competing on tight margins, forced to keep prices low or risk losing customers.

Manurewa's Happy Liquor store-owner Sanjesh Sharma said with 15 to 16 per cent margins, small businesses were turning over $15,000 a week. But after paying for staff wages, overheads and the alcohol itself, owners were "lucky" to walk away with $2000 a week, after working 70-80 hours: "We're competing amongst ourselves _ that way we're not making any money."

And most customers were price sensitive, he said.

"If I put one cent up _ people move. They don't care about petrol, they care about price. Out here people drink Steinlager. I'm selling it for $21. But other places sell for $20. They [customers] still moan `when is it going to be $20?' They don't want to take another dollar out of their pocket."

He dubbed those customers the $20 market, willing to drink anything in that price range, regardless of what it was. Independently owned shops couldn't compete with supermarket beer sales as many sold it at a loss in order to get people through the door, which left the door open to compete on spirits and Ready to Drink (RTD) mixes, he said.

Across south Auckland the Weekend Herald found virtually the same deals.

A four pack of Kristov Vodka Cruisers sells for $7.99; individual Woodstock cola and bourbon 440ml cans at 8 per cent alcohol for $2.50; lower-strength 5 per cent for $2; individual cans of Cody's, another cola and bourbon mix, at 5 per cent for $2.