International online gambling sites would be forced to pay tax on Irish bets under Opposition proposals revealed on Thursday.
The Labour Party said offshore bookmakers - including telephone and television operators - would be brought under a new 1.5% levy for the industry. This would replace the existing 1% tax in betting shops and raise €90m for the Horse and Greyhound Racing Fund.
Mary Upton, Labour's sports spokeswoman, said operators refusing the pay the levies would be banned in Ireland.
"Any company that refuses to register and pay the betting levy will be refused from offering a service to Irish customers," she said.
"Online operators who are not based in Ireland but who are providing a service to Irish customers and who refuse to register and pay the betting levy will be blocked by Irish internet service providers, upon the direction of the Government."
Ms Upton said the overhaul was needed to continue funding the horse-racing and greyhound industries.
Extra money raised would be used to double funding to local sports partnerships and support organisations working with gambling addiction, under the proposals.
Ms Upton said a recent ruling in the European Court of Justice in favour of Portugal, against a foreign gambling company, provided a precedent for their plans.
"It is important to point out that this levy will not affect any other markets that companies based in Ireland are active in," she said.
"Companies will pay the betting levy on their Irish operations only. Thus there is no incentive for any companies to move outside of Ireland."