A pirate radio station operating out of south-western Victoria has been shut down by the Australian Communications and Media Authority (ACMA) and the operator has been fined.

Terence Sulman was convicted, fined $600 and was ordered to forfeit all radio equipment, after pleading guilty in the Portland Magistrates Court.

The conviction followed an ACMA investigation into unlicensed transmissions on the 101.3 MHz band in Portland earlier this year.

Mark Loney, the executive manager of the ACMA's Spectrum Operation and Services branch, said Sulman had previously worked for a radio station so he had a "rough idea of what to do and he did it".

Mr Loney said setting up a pirate radio station was "unusual" and "serious".

"[Sulman] was trying to offer something like a local commercial radio station, so he sold advertising and sponsorship to local businesses," he said.

"[He was] knowingly operating an illegal radio station, attempting to make money out of it.

"So he wasn't just doing it as a hobby. He was attempting to earn an income out of it. So that's why we decided in this case to prosecute."

Mr Loney was confident the fine handed down by the courts would deter future operations.

"Not only is it unusual for us to fine people for running pirate radio, it's unusual for us to even prosecute," he said.

"Like many laws, almost everyone complies with them, but when people break them, particularly for commercial gain, then it's worth prosecuting them."