Bookings to the two countries collapsed last year after popular uprisings across the Arab world toppled veteran rulers in Tunisia, Egypt and Libya, and forced Yemen's president to sign away his powers.

"Developments in the Middle East and North Africa are very difficult to predict at this time," Taleb Rifai, secretary-general of the United Nations World Tourism Organization (UNWTO), told Reuters at the ITB Berlin travel fair.

"The situation in Syria is still unfolding from bad to worse. The situation in Yemen is very unclear. And the Arab Spring is not limited to any one particular country. Uncertainty is the name of the game now for the immediate future."

Tour operators and governments had expected tourism to bounce back, but that has proved not to be the case, with many holidaymakers preferring instead to seek winter sun in the Canary Islands, the Caribbean or the Maldives.

"We understand that (challenge) perfectly. We have to reassure them that Tunisia is safe," the country's tourism minister Elyes Fakhfakh told Reuters on the sidelines of the Berlin conference.

The number of international tourists arriving in North African destinations dropped by 12 percent to 16.4 million last year, and the Middle East saw visitor numbers decline by 8 percent to 55.4 million, according to UNWTO data.

The body sees growth for the overall Middle East of zero to 5 percent this year, though Rifai said there was a good possibility arrivals in Egypt and Tunisia could return to pre-crisis levels by the end of the year.

For the moment, Egypt in particular is still struggling following an 18 percent drop in tourist nights spent in the country in 2011, and much is riding on how the political situation changes over the next few months.

The problem has been compounded by a recent flurry of kidnappings of foreigners by Bedouin tribesmen in Egypt's Sinai Peninsula that has drawn attention to deteriorating security in the isolated desert region since the overthrow of President Hosni Mubarak.

"MIRACLES"

Nonetheless, Rifai said he believed the governments of Tunisia and Egypt had done a good job so far in their efforts to lure tourists back.

"I think they have done miracles, under the circumstances," he said.

Egypt has attended more than 180 trade fairs in the last year to promote its attractions, said Hisham Zaazou, senior assistant to the country's tourism minister.

It is also the official partner country at the ITB Berlin, the world's No.1 travel fair.

One bright spot for Egypt has been healthy numbers of Russian tourists, who have not been deterred by instability in the region.

"Our hotels in the Red Sea areas are filled with Russians", Ed Fuller, president of Marriot's international division, said.

"They're not intimidated."

Tunisia, which cut its economic growth forecast for 2012 this week, does not expect numbers to return to pre-crisis levels of 7 million visitors until next year.

"We fell to 5 million visitors last year. We hope we can make up one million of the shortfall this year, with the remainder in 2013," Fakhfakh said.

According to German travel association DRV, Germans have been among the first to return to Tunisia, with current bookings rising strongly after a drop of around 40 percent last year.

"I don't think we will be back to 2010 levels this year, but it is catching up a lot," DRV president Juergen Buechy said.

(Editing by Gareth Jones and Sophie Hares)

• A Permanent Economic Emergency