A senior Portuguese official has given the two bidders in the privatization of TAP Air Portugal three days to improve their offers, hinting the flag carrier's sale could be called off if they don't.

The government announced last month it had accepted to consider bids for 61 percent of the state-owned airline from David Neeleman, who founded Brazil's third-largest airline Azul, and from German Efromovich, owner of Colombia's Avianca. The financial terms were not made public.

The government has been analyzing the bids and wants final offers by Friday.

For the second time in a week, Economy Minister Antonio Pires de Lima said Tuesday "it is very important for the two bidders ... to make a greater effort. They have to present better offers."