Switzerland is one of the main transit countries for stolen artefacts from Iraq, whose archaeological sites contain some of the most important treasures of Antiquity.
Experts say the trade in Iraqi artefacts took off during the Gulf War, when ancient treasures were plundered and sold illegally in international markets.
"There's been a lot of looting going on in Iraq [since 1991]," Neil Brodie, coordinator of the Illicit Antiquities Research Centre in Cambridge, Britain, told swissinfo.
"That's when people first realised they could make a lot of money from selling archaeological objects and began [plundering] sites and museums."
Brodie says Switzerland's location and important antiquities market means it's a natural centre for illicit art.
"We know a lot of Italian material passes through Switzerland, and it's a pretty safe bet that material from Iraq is also passing through Switzerland," he says.
"The expertise and the financial resources are there."
But Brodie says the illicit nature of the trade makes it impossible to put a figure on its value.
There are an estimated 10,000 archaeological sites in Iraq, where some of the earliest cities in Mesopotamia were located.
The Federal Culture Office says Switzerland - the world's fourth largest art market - has gained a reputation as a "turntable for the illegal transfer of cultural goods".
It has put forward a new law to tighten the trade.
On Tuesday the House of Representatives approved the law in principle - despite stiff opposition from art dealers - but tabled amendments to it. The Senate has yet to debate the draft.
Switzerland is one of the few countries not to have joined the United Nation's Unesco Convention of 1970, which regulates the transfer of cultural objects in 94 nations and encourages international cooperation.
According to Unesco and Interpol, stolen art is the third largest illegal market behind drugs and arms trading. The problem is particularly acute in Switzerland due to the lack of legislation.
"The fact that it hasn't signed up to the Unesco convention is certainly linked to the fact that it's a thriving centre for antiquities," Brodie says.
Andrea Raschèr, who is in charge of law and international affairs at the Federal Culture Office, says the current Swiss laws are clearly insufficient.
"In effect, Swiss law treats cultural goods like ordinary merchandise," he told swissinfo.
"That's why the theft of a bicycle is treated in the same way as a the theft of a Poussin and it's easier to import an ancient vase than a tomato."
Although the Unesco convention dates from 1970, it took until 1992 for the Swiss government to consider a new cultural objects law.
It has taken a further ten years for a proposal to reach parliament.
Raschèr said the delay was due to the fact that the extent of the problem had only come to light in recent years.
"The scale of the problem only became apparent with the discovery of looted art from the Second World War," he said.
The proposed legislation has provoked outrage in the Swiss art world, which while agreeing the need for it, feels that the new law is too prescriptive and confusing.
Several dealers, museums and art associations have teamed up to make a counter proposal.
Art dealer and archaeologist, David Cahn, is president of the International Association of Dealers in Ancient Art. He is worried that traders could unwittingly fall foul of the new law.
"It's not good enough to have a heavily administrative penalty system without telling people precisely what they have to do," Cahn says.
"This leads to confusion and because it leads to confusion, it also leads to scandals."
But Cornelia Isler-Kerényj, an archaeologist and a representative for Unesco Switzerland, told swissinfo that the art world is worrying unnecessarily because the law would only affect a very specialised area of the market.
"It will only affect the traders in archaeological and ethnological art and absolutely not traditional art or modern art," she said.
Raschèr says the draft law would increase the period after which cultural goods of unknown origin can legally come onto the Swiss market from five to 30 years.
This will not only bring Switzerland into line with most other countries, but it will also help in the fight against the laundering of stolen goods, he says.
But if passed by both houses of parliament, the earliest that the new law is likely to come into force is 2004.
swissinfo, Isobel Johnson and Vanessa Mock
The trade in stolen Iraqi artefacts started after the Gulf War, when museums and archaeological sites were plundered.
There are an estimated 10,000 archaeological sites in Iraq, which was part of Mesopotamia.
Switzerland is the world's fourth largest art market.
The Swiss government says the country has a reputation as a "turntable for the illegal transfer of cultural goods".
Parliament is debating whether to tighten the laws to prevent trafficking.
Switzerland has yet to sign the Unesco convention of 1970, which regulates the transfer of cultural objects.
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