Brisbane's only Greens councillor has apologised for posing as a concerned resident in a hoax voicemail to a state MP, but has refused to pay a fine over the matter.

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The Councillor Conduct Review Panel has fined Cr Sri $1,300 for inappropriate conduct

The Councillor Conduct Review Panel has fined Cr Sri $1,300 for inappropriate conduct Cr Sri says he takes full responsibility and is sorry for the dishonesty, but he won't pay the fine

Cr Sri says he takes full responsibility and is sorry for the dishonesty, but he won't pay the fine Ipswich MP Jennifer Howard says her staff identified Cr Sri by matching his number with a previous email

Councillor Jonathan Sri, who lives in inner-city Brisbane, left the message on Ipswich MP Jennifer Howard's phone in January to protest against a controversial development at Deebing Heights in her electorate, which is outside the Brisbane City Council area.

"Hi, my name is, um, John — I'm a resident of Deebing Heights," he said in the recording.

"I'm just calling to raise my concerns about the development at the Deebing Creek Mission site — I don't think it should go ahead and I am hoping that Jennifer will speak out publicly against it."

Deebing Creek is earmarked for a new 925-lot housing estate, but traditional owners have been camping on the grounds to stop construction going ahead near a heritage-listed Aboriginal mission and cemetery.

The councillor's 23-second voicemail was referred to the Councillor Conduct Review Panel and last month he was fined $1,300 for inappropriate conduct.

Mr Sri said he took full responsibility for doing the wrong thing and was sorry for being dishonest.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 23 seconds 23 s Jonathan Sri ( ABC News ) Download 368.3 KB

"I was telling residents that if they wanted to stop the development, it might help to call their state MP," he said.

"Then I realised if I was telling residents to call their MP, I should probably give the number a try myself.

"This wasn't an attempt to mislead the public in any way, this was just a private voicemail message that was left on the spur of the moment."

Ms Howard said her staff figured out "John" was Cr Sri by matching the phone number with details in a previous email sent to her Ipswich office.

"We were pretty shocked to start with and then very appalled — is this the sort of person we want in Brisbane City Hall representing constituents with their issues?" Ms Howard said.

Cr Sri's voice message was objecting to a development on the site of a former Aboriginal mission. ( ABC News: Rachel Riga )

"Spur-of-the-moment decisions like that are something maybe you'd expect from a schoolboy, not from an elected representative."

Cr Sri said he would not pay the fine because the Councillor Conduct Review Panel was a "weird sham tribunal".

"I'm worried that if I pay it, that's going to legitimise a broken process," he said.

"It is regularly used to discipline non-LNP councillors who speak out against the establishment — this is essentially a kangaroo court."

Mr Sri said he would donate $1,300 to a local charity instead.

"The real crime is that the State Government is allowing private property developers to bulldoze native bushland on the site of a former Aboriginal mission against the wishes of the traditional owners," he said.

Ms Howard said Mr Sri's behaviour was "bizarre" and it was unnecessary for him to get involved in Ipswich matters.

"There's absolutely no need for me to have a conversation with a Brisbane City Councillor about an issue in my electorate, but I'm very happy to receive a letter of apology," she said.