Fences were set up around the site in recent weeks, prompting protests from Brisbane City Council Greens councillor Jonathan Sri.

On Thursday, workmen began placing the sandstone blocks under the bridge, with works expected to continue until mid-December.

Housing Minister Mick de Brenni said the state government was "committed" to providing pathways out of homelessness for people staying under the bridge.

"We are working closely with a range of agencies, including Micah Projects, to develop a response to this issue and help those people sheltering under Kurilpa Bridge," Mr de Brenni said.

"The response devised includes providing housing assistance to those sleeping rough at the bridge site and landscaping works on land under the bridge."

Cr Sri, in a live video shot outside the worksite on Thursday, called the works "cruel" and "disgusting".

Cr Sri also challenged local member and Deputy Premier Jackie Trad on the works being conducted in her electorate.

But Mr de Brenni said the state government had worked to ensure safe housing had been provided for all the people staying under the bridge before the "landscaping" works began.

"A consultation process was undertaken to advise people camping at the site of the works and to arrange suitable housing and support for them," he said.

"Through these collaborative efforts, assistance was provided to all people who had been camping in the area.”