According to the Evening Standard, a leaked Department of Culture, Media and Sport memo strongly opposes a pre-watershed ban on alcohol advertising, describing its implementation as "completely speculative".
The memo also questions whether a ban would have any real effect on binge drinking, stating "under 18s probably watch post 9pm ads anyway".
According to the paper, Whitehall officials believe that a ban could cost TV channels £100m.
The memo's disclosure comes just ahead of the publication of a Department of Health and Home Office-commissioned independent review examining the links between alcohol prices, promotions and the harm to health caused by alcohol abuse. The review is also expected to recommend a ban on alcohol promotions on billboards and near schools.
Public health officials and some Labour MPs have been lobbying hard for a ban on alcohol advertising on TV programmes broadcast before the watershed. They have voiced concerns that the enticing imagery used in alcohol ads is attracting pre-18s to drink.
Current legislation means that alcohol brands cannot advertise on pre-9pm TV shows watched predominantly by children. However, campaigners are concerned that programmes such as soaps and reality TV, which attract a higher proportion of adults, are still popular with children.
Earlier this month, Gordon Brown signalled his backing for tougher rules on advertising junk food by appointing Labour MP Mary Creagh, a vociferous campaigner for a ban on junk food ads, as the chairman of a group to draw up public health proposals for the party's general election manifesto.