Dustin Johnson of the United States tees off on the 5th hole during day one of the LIV Golf Invitational at The Centurion Club on 9 June 2022 in St Albans, England. (Photo: Matthew Lewis / Getty Images) 
The advocacy group 9/11 Justice criticised the circuit in a television advertisement in Florida ahead of the Miami tournament and will host a news conference on Thursday, while urging former US president Donald Trump to cut ties with LIV.
Fifteen of the 19 hijackers on September 11 were from Saudi Arabia. The kingdom has long denied a role in the attacks, which killed nearly 3,000 people.
Bankrolled by Saudi Arabia's Public Investment Fund, LIV has attracted some of golf's biggest names away from the flagship PGA Tour. But critics say it amounts to "sportswashing" by a nation trying to improve its reputation amid ongoing criticism of its human rights record.
Saudi Arabia's government has denied accusations of human rights abuses.
"This is the second LIV tournament hosted by Donald Trump at his golf courses this year, and that is painful and really disappointing," Brett Eagleson, president of 9/11 Justice, said in a statement.
"The evidence of Saudi government officials' participation in this attack on America could not be clearer."
Another group, 9/11 Families United, sent an open letter condemning golfers who joined LIV in June.