Irish citizens living anywhere in the world will continue to be able to fund Northern Ireland's political parties, it has emerged.
But British citizens abroad wishing to make donations will have to be included on the United Kingdom electoral register.
The apparent anomaly was confirmed as a new system requiring the province's parties to make quarterly reports of their donations to the Electoral Commission came into force.
The commission called the system "semi-transparent" and said it was confident full disclosure of who is funding the parties should be possible after 2010.
And it was also confirmed that loans to the parties will remain unregulated until the Northern Ireland Office introduces legislation to close the loophole.
Sinn Fein, the DUP, SDLP, Ulster Unionists, Alliance and the smaller parties have, however, signed voluntary letters of undertaking not to receive loans from unpermissible sources.
Roisin McLaughlin, a senior officer with the commission, said the new system represented "a major step forward" .
The commission confirmed, however, while it will have access to regular reports on party donations, it cannot make the information public - unless the cash comes from an impermissible source.
'Permissible' donors include individuals on the register, firms and businesses registered under the Companies Act, trade unionists, building societies, certain trusts as well as friendly, industrial and provident societies.
The commission said the fact that donations can also be accepted from permitted Irish sources, which include the above as well as Irish citizens living anywhere in the world, was consistent with the principles of the Good Friday Agreement.
"We can make public information about impermissible donations but we won't be able to make public the name of the donor," Dr McLaughlin added.
From the end of next January, the parties will be required to submit details of money, property, sponsorship, subscription fees as well as certain payments from the taxpayer, for example the assistance they receive in grants from the Assembly.
They are required to record details of all donations over £200 and the rules prevent individual donors from making several donations below the threshold, since sources will be aggregated.
Apart from the parties as entities, donations to individual MPS, MLAs, MEPs and councillors must also be disclosed.