Customs staff were assured that such reporting ''is not about dobbing people in'' but they could expect to be disciplined if they ''make a negative comment on Facebook about a specific Customs and Border Protection corporate decision made by the senior executive''.

Paranoia within Customs has been fuelled by recent revelations that a few officers have been socialising out of hours at nightclubs and gyms with Middle Eastern crime figures and members of bikie gangs, including the Comancheros. Some Customs staff are understood to be romantically linked to known criminals. One crime figure was invited to Customs' Christmas party.

From Friday, staff were told it would be ''a legal mandatory requirement for all Customs and Border Protection workers to report any suspected serious misconduct''. Staff who witness ''serious misconduct'' and do not report it will be investigated and could lose their jobs.

Under the new drug and alcohol testing regime, which begins next month, Customs staff can expect to be tested for drugs and alcohol any time during work hours. The legal blood alcohol limit to drive is 0.05 per cent but Customs is introducing a limit of 0.02 per cent.

One section of the document states that staff can only drink alcohol at ''designated social venues'' in their off-duty hours, but a Customs and Border Protection spokesman clarified that this applied only to venues on Customs premises and that ''there is no restriction on which venues officers can attend outside work hours''.