The Australian Greens is amplifying its opposition to Labor's ISP-level internet filtering proposal with plans to host a 'Stop the Internet Filter' forum in Sydney next month.

Announced Wednesday, the event will be attended by Greens Senator Scott Ludlam, Greens NSW Senate candidate Lee Rhiannon and Sydney-based journalist and blogger Antony Lowenstein.

Attendees have been invited to "discuss internet censorship issues" with the trio in the Sydney suburb of Surry Hills on 7 July.

"Communications Minister [Stephen Conroy] has announced plans to introduce an internet filter which will restrict Australians' access to the internet and establish a system for widespread government censorship of the internet," the politicians posted.

Ludlam has been a vocal opponent of the filter, tabling in the Senate on Monday an anti-filter petition containing more than 19,000 signatures.

Other filter protest events have been organised by Electronics Frontiers Australia, Block the Filter and Stop the Filter earlier this year, the latter of which was attended by Ludlam.