CAIRO -- Staff members at a Riyadh hospital got a surprise
when they looked at the fine print on the paper cups they
were using.

Workers in a storeroom at a Dubai hospital were similarly
shocked when they took a close look at the tags on a large
shipment of uniforms, towels and sheets.

The labels said "made in Israel," according to recent
newspaper reports from Saudi Arabia and the United Arab
Emirates, both of which have laws that ban imports from
the Jewish state.

Experts say the camouflaged trade -- just a small portion
of such imports that have received publicity -- has been
going on for years between Israel and its officially
hostile Arab neighbours.

The hidden trade is worth about $400 million a year --
about two and a half times what Israel sold to its
official Arab trading partners, Egypt and Jordan, in 2004
-- said Gil Feiler, the director of Info-Prod Research, a
Tel Aviv consultancy specialising in Arab markets, and an
economic professor at Bar Ilan University.

Others say such estimates are significantly inflated.

"All the figures are very sexy for the press, but the
reality is much less than what is written," said Dan
Catarivas, foreign trade director at the Israeli
Manufacturers' Association.

The true amount of Arab imports from Israel is impossible
to establish because neither side makes it public, with
Israeli-made goods moving to Arab customers through third
countries -- Cyprus or the Netherlands, for example, which
list the shipments as local exports.

An Arab lawyer who specialises in trade, Omar Obeidat of
Al Tamimi & Co. in Dubai, said the Arab League boycott of
Israel is well enforced, despite the hidden trade through
third countries.

"The only person who can confirm is the Israeli party to
this covert operation," Obeidat said, when asked to
estimate the worth of goods flowing to Arab nations.

Feiler, who has written a business guide to Israel in
Arabic, refused to give more than rough outlines of the
trade, which he supports.

Israeli exports to Arab countries, he said, are mostly
from three categories: Agricultural equipment, such as for
irrigation -- a field in which Israel leads the world,
animal vaccines and "technological knowledge and
components" -- about which he refused to elaborate.

Feiler said the Israeli origins of products is hidden by
methods other than third-country exports. Arabs of
Lebanese origin in Israel sell counterfeit Lebanese
certificates of origin complete with forged government
stamps. Some Israeli factories have departments of
so-called quality control -- where any Hebrew writing or
`made in Israel' marks are removed from product
components.

"I saw it with my eyes," he said.

There are even ships that sail from the northern Israeli
port of Haifa to Beirut, Lebanon -- "there is a way to do
it," Feiler said, adding that the Beirut Port Authority
would deny the practice exists.

Sending Israeli products to Gulf states is the easier,
said Doron Peskin, research director at Info-Prod. "The
difficult thing is not to make mistakes."

What probably happened in case of the paper cups, for
instance, was a delivery manager shipping the wrong boxes
-- those not stripped of Israeli markings. The Arab News
quoted the purchaser of the cups as saying they arrived in
a cardboard box that looked exactly the same as the ones
he normally received.

Bahrain's recent decision to abandon the Arab boycott
provoked an uproar in the Gulf state. While legislators
sought to reverse the decision, the government insisted
the move did not signal a normalisation of ties with
Israel, but was implemented to ensure the US Congress
approved a free trade agreement with Bahrain.

The United Arab Emirates and Oman are expected to follow
Bahrain's lead as they negotiate free trade agreements
with the United States. When Saudi Arabia joined the World
Trade Organisation last month, it quietly said it would
treat all members equally. Israel is a WTO member.

But there is a big difference between decisions in
principle and the open flow of Israeli goods. As the big
Saudi food retailer Turki Al Sharbatly said recently: "If
I bring Israeli products into my shop, no one will deal
with me."