Moves to finalise approval for a badger cull are "very well advanced" according to Natural England, amid the threat of a last-minute legal challenge by opponents.
But the agency, responsible for issuing the licenses for the two pilot areas in West Gloucestershire and West Somerset, was unable to say when the paperwork would be signed off, although it was "working towards" the cull starting this year.
It came as the Badger Trust has sent a "pre-action protocol letter" to Natural England in a bid to establish whether the charity has grounds to launch a legal challenge.
Official statistics suggesting higher-than-expected badger populations in both areas, could also have implications for meeting cull targets in the available timescales.
MPs at Westminster are also due to debate the cull on Thursday amid calls to halt the controversial control measure.
Supporters of the cull say the move is necessary to tackle TB in cattle because the wild animal spreads the disease to livestock, costing farmers and the taxpayer millions of pounds a year.
But opponents argue the cull will not have a significant effect in reducing the disease in livestock, and want the focus to be shifted on to vaccination.
In the South West almost a quarter of farms were under movement restrictions last year.
A spokesman for Natural England said of the progress of the licences: "We are in the final stages of finalising them. People are working towards starting it this year."
Badger Trust spokesman Jack Reedy said: "We have written a letter to see whether it is possible for us to mount a legal challenge. We need to see by this exchange of correspondence if there are grounds to take action. The outcome of that will determine what we do next."
Natural England was considering the contents of the Badger Trust letter and would respond in due course, the spokeswoman added.
It was recently revealed the "best estimate" for badger numbers in the cull areas was 3,600 in west Gloucestershire and 4,300 in West Somerset. This is twice as many as first thought in the west Gloucestershire cull zone and about 60% higher than the original estimate for west Somerset.
As a result, concerns have been raised over meeting the targets of removing at least 70% of badgers in the cull areas within the required time period.