The list comprises a small number of commonly used therapeutic medications that will be permissible at low levels in competition horses, including the powerful anti-inflammatory phenylbutazone.
The list, passed narrowly in a vote by the International Equestrian Federation's General Assembly last month, replaces the zero-tolerance policy in respect of these drugs that has existed for 20 years.
However, a worldwide backlash by major equestrian nations has seen the equestrian sport's world governing body delay its original January 1 introduction, pending further consultation.
New Zealand, represented at the Copenhagen meeting by president Jennifer Millar and chief executive Jim Ellis, voted against the progressive list.
Major equestrian nations have already outlined their positions on the list, with the British federation voicing opposition, while the United States supports it.
A veterinary committee within the Irish body has raised serious concerns, while in Germany the federation president has spoken strongly against it.