The call followed a preliminary report by FIFA's Ethics Committee that found "overwhelming" evidence Warner was involved in a cash-for-votes scandal rocking the organisation.
Warner, who is the transportation minister in Trinidad and Tobago, quit FIFA on Monday. His decision led FIFA to drop an investigation into bribery allegations against him. He has repeatedly denied any wrongdoing.
Keith Rowley, an opposition leader, told reporters Prime Minister Kamla Persad-Bissessar should dismiss Warner from his cabinet post.
"It is wholly unacceptable for an individual to be so disgraced in an international organisation, falling short of matters of ethics and integrity and still be allowed to remain as a cabinet minister," he told reporters.
The findings in the FIFA report "means the prime minister of Trinidad and Tobago now has a decision to make," Rowley added.
Before stepping down from FIFA, Warner was being investigated in a bribery scandal linked to the campaign of former FIFA presidential candidate Mohamed Bin Hammam.
Warner and Bin Hammam were both suspended in late May after accusations they attempted to bribe delegates of the Caribbean Football Union with inducements of $40,000 to vote for Bin Hammam.
Qatari Bin Hammam, who has also denied wrongdoing, eventually quit the race for the presidency, paving the way for FIFA President Sepp Blatter to be re-elected on June 1 for a fourth term.
