His party and the Sikhs would oppose construction of the memorial by Damdami Taksal chief Harnam Singh Dhooma, he told a press conference here.
Mann alleged Dhooma had close relationship with Chief Minister Parkash Singh Badal and his Deputy Sukhbir Singh Badal.
The SGPC had thrown all norms of Sikhism to winds by extending special favour to Dhooma for construction of the memorial, he said.
Dhooma also had close relationship with several BJP leaders, the SAD (Amritsar) chief said.
A great Sikh personality with pious image should be chosen for construction of the memorial, Mann said.
He said the memorial constructed by Dhooma would be demolished immediately.
Mann asked Akal Takht Jathedar Gurbachan Singh to intervene in the matter.