Activist group Moviment Graffitti will hold a public protest over the massive project planned for the Villa Rosa area, behind St George's Bay.
The protest will be held on at 10.30am in St George's Bay.
The protests comes a week after Times of Malta revealed that the Cabinet had instructed the Planning Authority to start a process to amend local plans to accommodate it.
Times of Malta also revealed on Sunday that a six-point plan to change St George's Bay's Villa Rosa local plan subsequently published by the Planning Authority on Tuesday was lifted almost word-for-word from a list of suggestions drafted by the project's developers and later presented to Cabinet.
"This shows that developers not only dictate the law, but they do it literally too," Graffitti said in a Facebook post.
The group said the proposed project would signal the ruin of Wied Ħarq Ħammiem.
"The magnitude of the impact that the planned mega-development of a 34-storey tower and two 27-storey ones will have on the valley is expected to be very high. The geomorphology of Wied Ħarq Ħammiem is still well-preserved, and the current landforms in the floodplain will be modified through the proposed excavations," the group said.
The valley is characterised by a deep gorge with rock slopes with surface karst features and the dry watercourse is well developed, especially the section passing through Villa Rosa, Graffitti said.
"The mega-development is set to obliterate the still-extant natural valley landform in the inner part of the site towards Wied Ħarq Ħammiem. The development will signify the ruin of this valley that still stands largely intact in the midst of an urban area."
The valley hosts olive trees, date palm trees, tamarisk trees and aleppo pine trees, all of which fall under Schedule II of Trees and Woodlands Protection Regulations, 2011.