Advertising executives have disputed two reports that claim the industry grew in the region last year.
In an escalating row, several of the biggest media agencies insist that advertising spending declined by 10 per cent last year.
That is despite the findings of Ipsos MediaCT, one of the region's two main advertising monitoring companies, which said spending in the Arab advertising industry grew by 9.5 per cent last year. A rival monitoring agency, the Pan Arab Research Center (Parc), last week reported a 4 per cent rise in the Arab advertising market for last year.
Eddie Moutran, the chief executive of the advertising agency Memac Ogilvy in the Middle East and North Africa (Mena), said the findings were flawed. "I don't agree with it," said Mr Moutran in reference to Parc's figures.
"There has been a drop of anywhere between 10 and 17 per cent. Some companies don't like to invest in a volatile environment," he said.
Parc estimated the total Arab advertising market was worth US$14.3 billion (Dh52.52bn) last year. But Mr Moutran said the true figure was between $3.5bn and $4bn.
He said the disparity in figures was due to Parc's measurement of advertising according to the rate card - the official fees published by newspapers and TV broadcasters.
In reality, most Middle Eastern media outlets give huge discounts on the published rates, as well as free advertising to loyal customers.
"What you see is not what you pay for," said Mr Moutran. "In a market like this, negotiations become a lot more acute than before. So people get a lot more benefits for their dollars than in previous years."
Other advertising executives agreed that the market shrank last year.
Elie Khouri, the chief executive of Omnicom Media Group in the Middle East and North Africa, said last week that true spending on advertising fell by 10 per cent.
Elie Haber, the managing director of the media planning agency Mindshare in the UAE, concurred.
"The reality on the ground is that the market had shrunk by no less than 10 per cent," said Mr Haber.
The impact of unrest in the Arab world was one of the key factors behind lower spending last year, Mr Haber added.
"In Egypt, the Arab Spring is not over yet; Bahrain has a major impact on Saudi Arabia, where investors put on hold all their investments," he said.
Sami Raffoul, the founder and general manager of Parc, defended his company's figures.
"We have been reporting the figures every single day since June 1976 using a methodology that is applied worldwide," he said.
Mr Raffoul acknowledged that Parc could not measure the net spending on advertising because contracts between media owners and advertisers were confidential.
But he said estimates that the industry could be worth just $3.5bn "contradict the magnitude of investments" made in the region.
Ipsos reported that the advertising market in the Mena region had increased to $17bn last year.
Elie Aoun, the president for the Middle East, Africa and Pakistan at Ipsos MediaCT, accepted that ad spending had not grown last year - despite what his company had reported.
He said the Ipsos figures showed an increase because the company started measuring advertising in more media outlets last year.
"Overall, I would say that it's kept the same level of expenditure," said Mr Aoun.
"[The reported rise was] because of our increased coverage of new media. In some markets we have added a lot of new media that were not monitored in the previous year."