NEW YORK, Sept 21 (Reuters) - Western nations are sending representatives to India, home to 90% of the world's cutting and polishing of the rare gems, to discuss potential effects of any G7 restrictions on imports of rough Russian diamonds, two Biden administration officials said.

"There's a trip next week to India, a number of countries are going to sort of verify certain elements of implementation. I think that will be really important to people's decisions," a senior official told Reuters on Wednesday.

A second U.S. official said on Thursday that representatives from the United States and its allies from the G7 group of most industrialised countries, as well as Belgium, will travel to Mumbai and Surat, a city where about 80% of the world's diamonds are polished.

The G7 countries are working on a tracing system that would allow them to block imports of stones mined in Russia, the world's largest producer of rough gems.

The plan could transform the global diamond supply chain, but implementation will depend heavily on India, whose diamond industry employs millions of people.

The Biden administration officials spoke on condition of anonymity on the sidelines of the annual gathering of world leaders at United Nations headquarters in New York.

Officials in Belgium - where the historic city of Antwerp is the world's No. 1 diamond trading hub - expect the G7 to announce the ban in coming weeks in a bid to tighten a squeeze on Russia's capacity to finance the war in Ukraine.

Belgium, which is not in the G7 but is a member of the European Union, has been blocking any sanctions on Russian diamonds sought by hawks in the EU.

The EU, where imposing sanctions requires unanimous backing of all 27 member states, has imposed 11 rounds of trade restrictions on Russia as punishment since Moscow invaded Ukraine, attacking by land, sea and air in February 2022.

Russian diamonds and the state-controlled miner Alrosa have so far remained off-limits as Belgium said trade lost in Antwerp would be rerouted elsewhere unless any EU imports ban is backed by more countries globally.

A leading Russia critic, Poland this week launched a fresh call for EU sanctions on Russian diamonds, the sales of which brought Moscow more than $4.5 billion in 2022. The EU bought some $1.5 billion worth of Russian diamonds last year.

Following Moscow's invasion of Ukraine, Washington imposed sanctions on Alrosa and barred the import of non-industrial diamonds of Russian origin into the United States. (Reporting by Daphne Psaledakis and Humeyra Pamuk, Writing by Gabriela Baczynska; Editing by Howard Goller)