Increased use of non-tariff measures (NTMs) by governments can have a significant impact on trade and transparency needs to be improved in this regard, an annual report of the World Trade Organization (WTO) said Monday.

The World Trade Report 2012 examined why and how governments use NTMs, such as technical barriers to trade (TBT) regarding standards for manufactured goods, sanitary and phytosanitary (SPS) measures concerning food safety and animal or plant health, as well as domestic regulation in services.

Such measures can serve legitimate public policy goals, such as protecting the health of consumers, but they may also be used for protectionist purposes, said the report.

The report found out that WTO members have increased use of TBT and SPS measures, which are the most burdensome for developing countries' exporters, since the mid-1990s.

WTO Director-General Pascal Lamy said NTMs are less about shielding producers from import competition and more about the attainment of a broad range of public policy objectives.

"The challenge is to manage a wider set of policy preferences without undermining those preferences or allowing them to become competitiveness concerns that unnecessarily frustrate trade," he said.

The relative scarcity of information on non-tariff measures is partly because that these measures are more difficult to measure than tariffs, the report said.

But not all these measures have a negative impact on trade, it said.

While regulatory standards restrict trade in agricultural products, the existence of standards often has a positive effect on trade in manufactured products, especially in high-technology sectors, according to the report.

Moreover, the harmonization and mutual recognition of standards is likely to increase trade, it said.

Besides transparency, the report also called for more effective criteria to identify why a measure is used, a deeper integration and regulatory convergence, as well as capacity-building in improving international cooperation.