The advantage of restricting import of gold to designated agencies is that the regulators can fix monetary limits on import during the transition. The domestic transactions of gold imported through the designated agencies could be more easily tracked and would be channelled for making jewellery for domestic use or export. This would also boost exports substantially.
On this logic, it will be necessary to discourage liberalised import through NRIs. However, it is possible to charge less import duty when designated agencies import, to discourage the NRI route. In any case, nominal import duty is a pre-condition for liberalised imports. Incidentally, under the liberalised regime, the sale of gold by designated agencies has to be freely permitted to domestic jewellery units.