BAGHDAD'S al-Zawra Zoo is enjoying a boom, and not just in attendance - its Siberian tigers gave birth to twins, part of a rush of new arrivals swelling the park's population.

From the dark days of 2003, in the aftermath of the US-led invasion that left the zoo in chaos, the central Baghdad attraction is enjoying a surge in visitor numbers as security in the capital improves and its animal population soars.

''It means a lot to me,'' says the zoo's director, Adil Salman Mousa, as the twin tigers prowl and play behind him. ''After the war, we reached a point where the US told us to close the zoo because there was nothing left. But we were convinced we could bring it back.''

The 53-year-old proudly lists the accomplishments at al-Zawra in recent years: in addition to the as-yet unnamed Siberian tiger cubs, the zoo has also seen the birth of a Bengal tiger, as well as bears, gazelles and stags.

Then there are the animals sent from around the world: two jaguars arrived just days ago and are in quarantine. Other new arrivals include crocodiles and chimpanzees, with zebras due within days and giraffes and elephants on the way next year.

In all, al-Zawra houses more than 1000 animals, a far cry from the dozen or so in the immediate aftermath of the invasion, when hundreds of beasts were stolen, killed or left to die in their cages At the time, shortly after the invasion, Mr Mousa returned to the zoo - once the biggest in the Middle East - at great personal risk to try and save the few surviving animals. In time, he secured overseas funds and support from international conservationists to build it up again. The growth in animal numbers has coincided with an increase in visitors as Baghdad and Iraq have become safer.

According to US officials, civilian deaths and injuries as a result of violence have dropped by 90 per cent across the country since June 2007. ''In the first few years after the war, violence was everywhere, so few people came, but in 2007 there were 120,000 visitors throughout the year,'' Mr Mousa says.

That figure rose to more than a million in 2008, and has already topped more than 2 million this year. The zoo's attendance figures show that around a million people visited over the Eid al-Fitr holiday in September, following the fasting month of Ramadan.

''This is the only good place in Baghdad to come with your family,'' says Ahmed Hassan, a 29-year-old software engineer, as he cradles his newborn daughter, Aya, in his arms. 'Years ago, when I felt sad and didn't want to sit at home, I would come here.''

The zoo also remains an affordable trip for a large family: while a ticket to Iraq's National Theatre costs 10,000 dinars ($A9.40), adults pay only 500 dinars each for entrance to al-Zawra, and children under the age of 10 get in free.

While al-Zawra has come a long way in six years, Mr Mousa has plans for further expansion and improvement. ''Most people, they love the zoo - everyone says it's a great zoo, but we want to make it better,'' he says.