Former BBC Middle East correspondent Tim Llewellyn has joined forces with the NUJ and MPs to campaign against proposals for the corporation to carry ads on international pages of its website.
The BBC Trust was due to discuss the proposed scheme on Wednesday.
According to the NUJ, more than 200 reporters, editors, domestic and foreign correspondents and technical staff have signed a petition opposing the move.
The NUJ argues that the advertising plan "would permanently damage the BBC's distinctive reputation abroad, and in the UK , as an independent public service broadcaster".
Llewellyn said: "Another important element of the BBC's commerce-free identity and honest service of unbiased news, ‘free at the point of delivery', as New Labour might say, is sliced away — a significant step on the way to eroding all the institution has stood for for more than 80 years.
"Money is the excuse, although the BBC is richer and more powerful than it has been in its history. Some of the money needed could have been released from the bosses' hyper-salaries, more suitable for captains of industry than deliverers of a public service."
So far, 45 MPs have signed an Early Day Motion tabled by the NUJ's parliamentary group, urging the BBC to abandon the plans. Some also signed an open letter to the national press this week.
The campaign is supported by the International Federation of Journalists, the Campaign for Press and Broadcasting Freedom and the British Internet Publishers' Alliance, which represents most national newspaper websites.