The Dutch defender also says he is having to change his home telephone number ‘weekly’ because of sectarian abuse he and his family receive.
In an extraordinary outburst on the Old Firm’s continuing problems with bigoted fans, Ricksen said: "If you’re Catholic and you play for Rangers, then you are a Protestant.
"If you play for the Protestant people, you don’t play for the Catholic people."
Ricksen added: "If you can’t handle that, if you’re really a Catholic and you feel too much about it, you don’t come to Rangers. You stay away.
"You’d better go to the other side [Celtic] or there will be a lot of problems for you."
The player’s comments suggest that Rangers have failed to throw off their reputation for being anti-Catholic, despite ditching their policy of not signing Catholic players 13 years ago.
In 1989, Rangers signed Maurice Johnston, and since then have taken on a number of Catholic players. Lorenzo Amoruso, a current player, was made the first Catholic to captain Rangers in 1999.
Politicians and Church figures last night insisted that the comments of Ricksen - a Protestant - demonstrated that more effort had to be put into combating sectarianism.
Liberal Democrat MSP Donald Gorrie said it reinforced the need for the law to be amended, so crimes motivated by sectarianism attracted greater penalties.
He said: "Ricksen is clearly showing we have not made enough progress in tackling this issue."
A spokesman for the Catholic Church in Scotland said: "The brave words of Fernando Ricksen are a sad indictment of our society. It is deplorable, indeed shameful that Glasgow is perhaps the only city in Europe in which a professional footballer is required to deny his faith in order to achieve sporting success."
He continued: "It sometimes takes the objectivity of one born outside the cauldron of the west of Scotland to reveal to us the ugliness of this aspect of our culture. Those who bring shame on Glasgow and Scotland by peddling such bigotry need to know that their attitudes are utterly unacceptable in modern Scotland."
Ricksen also revealed that he had been forced to change his telephone number repeatedly in recent months after receiving a torrent of abusive calls of a sectarian nature.
On one occasion, the phone was answered by his 12-year-old stepson, Wim.
Ricksen said: "He’s a big boy who’s used to it and knows enough about the situation to handle it, but it’s not nice. He picks up the phone before he goes to school in the morning and hears someone swearing at him. That I can’t understand."
A spokesman for Rangers said they would not comment on Ricksen’s remarks until they had spoken to the player.
He added: "We are strongly opposed to inappropriate behaviour driven by sectarianism or racism. In support of this we pursue and seek to take action against all offenders."
Ninety-five supporters are currently banned from attending Rangers matches - many for sectarian abuse.
A spokeswoman for Celtic said that, as well as being involved in several projects with other agencies, the club was pushing the Scottish Executive to help drive home the anti-sectarian message to schools.
"Everyone is in agreement that the way to tackle this is to speak to young people, asking them to question the things they hear and the things they say. Hopefully this is something we can then consign to history in years to come."
Meanwhile, a new poll has found that 69% of people feel neither Rangers nor Celtic do enough to deal with sectarianism among their fans. System Three interviewed 900 people for the BBC Scotland survey.