Police will allege Mitchell Fitton admitted to ordering the guns from a company in Minnesota in the US in November 2019 with the intention of having them shipped to his address in Oak Flats.

The parcel made it into Australia but was stopped and inspected by Australian Border Force and Customs officials at their Sydney holding facility on February 27.

Inside the box officials discovered a Ruger Blackhawk .177 calibre soft air rifle, a Smith and Wesson brand 0.177 calibre air pistol, and a Umarex Ux Brodax .177 calibre soft air revolver. All items are considered firearms under the law, despite being air pistols.

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Police raided Fitton's Wentworth Street home on Wednesday, allegedly uncovering a range of drugs, cash, explosives and the guns.

It is alleged police found more than a kilogram of cannabis, plus small amounts of ecstasy and methamphetamine, all of which Fitton claimed was for person use.

They also discovered 16 cannabis plants, a large quantity of cannabis seeds, a slingshot, fireworks, three tins of ammunition and $10,150 in cash.

When asked about the guns, Fitton allegedly admitted buying the items, saying he was of the belief he wasn't doing anything wrong.

The 19-year-old also claimed the cash found was part-savings from cash jobs as a tiler, and part-winnings from the pokies.

Fitton was charged with drug and firearms offences and remanded in custody. He sought bail in Wollongong Local Court on Friday but it was refused. The case will return to court on Monday.