A new regional bloc grouping Russia, Belarus and Kazakhstan that could apply jointly for WTO membership will open up massive business opportunities, Kazakh President Nursultan Nazarbaev said Friday.

The creation of a new customs union comprising the three ex-Soviet states was declared in a surprise announcement last week by Russian Prime Minister Vladimir Putin, who said the countries would unify their bids to join the World Trade Organization.

"The customs union with Russia and Belarus opens new possibilities for our businesses," Nazarbayev said in a statement posted on the website of the presidential administration.

"It is an enormous market with a population of more than 170 million and a total GDP of nearly two trillion dollars (1.4 trillion euros). Kazakh businesses must develop these markets and we are creating the necessary conditions for that."

Energy-rich Kazakhstan -- Central Asia''s largest economy -- has been severely hampered by plummeting commodity prices resulting from the global financial crisis.

The customs union will open new markets and allow private business to become the "locomotive for the development of the country," Nazarbaev said.

Belarus and neighbouring Russia already have a formal customs union, which Kazakhstan is set to join.