Police have arrested four men allegedly involved in trafficking cocaine through a taxi “delivery service” in Sydney.

The men, in their 30s, were expected to be charged following investigations into a syndicate suspected of using cabs to deliver hundreds of one-gram cocaine deals a week to “customers” throughout Sydney.

NSW Police Superintendent David Donohue told media on Friday the service was suspected to have operated throughout Sydney, “from the foot of the mountains right throughout the CBD”.

The taxi licences of the men concerned are under investigation and their vehicles will be seized.

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“I wouldn’t say it’s a new norm but it is a novel way of getting your drugs, something I, in my career, I haven’t experienced this way of distributing drugs,” he said.

He said police were still investigating how long the syndicate had operated for and warned others against the practice.

“We’re aware of your methodology and we have very good investigators and … techniques to investigate these things – you will be caught,” he said.

“At the moment this is a large investigation with a significant amount of investigation trails to follow and anyone who has used this service can expect a knock on the door.”

One 29-year-old North Bondi-based graphic designer, Gina – whose real name was withheld by Fairfax Media – told The Sydney Morning Herald: “It’s pretty simple really. You get a number, send them a text and then they drop off the coke”.

“There are a couple of taxi drivers that I know do it. You get given the number from someone originally and then every couple of months you get sent a text with a new number to use.”

Officers from the tactical operations unit and the riot squad raided five homes in Auburn, South Granville and Guildford about 6.00am on Friday.

The men are currently assisting police with their inquiries.