The NSW government will urgently seek to close a loophole in liquor licensing laws that has allowed internet-based sly grog salesmen to run 24-hour booze delivery services without a licence.

Last week Fairfax Media reported that the services, The Beer Baron and The Blind Pig, were exploiting loopholes in NSW laws that allowed them to operate on an unlicensed basis as long as they treat sales as "gifts".

The Beer Baron ... Jed Clarke.

The services use Facebook, websites and word of mouth to market their wares.

It is illegal to sell takeaway alcohol after midnight, including deliveries, but the NSW Office of Liquor, Gaming and Racing (OLGR) wrote to the owner of The Beer Baron, Jed Clarke, effectively giving him permission to operate without a licence.