* Stops supplying foreign exchange points
* Other foreign currency sales already halted
* Running out of reserves (Changes source, adds details, background)
MINSK, March 22 (Reuters) - Belarus's central bank has halted foreign currency sales to local banks in a bid to save dwindling reserves, according to a document seen by Reuters on Tuesday.
The former Soviet republic is running out of foreign currency reserves due to a large trade deficit, earlier overspending by the government and high demand for cash dollars and euros among the population.
The central bank this month halted most foreign currency sales to banks by requiring them to be booked 30 days in advance. It did, however, continue sales of foreign currency in cash for foreign exchange points.
But in a letter to local banks on Tuesday, it said an earlier document allowing for cash foreign currency sales was now cancelled.
"Banks now have to rely on their own long positions in foreign currency," said a Belarussian banker, speaking on the condition of anonymity. "(But) the reality is that banks have no long positions in foreign currency."
The central bank did not confirm or deny the validity of the document. Its foreign currency reserves shrank 20 percent in the first two months of this year to $4 billion and now cover just a few weeks of imports.
Belarus has asked Russia and other former Soviet states for $3 billion in loans which officials say would help the country avoid devaluation but some analysts say it is still very likely. (Reporting by Andrei Makhovsky,Additional reporting by Nastassia Astrasheuskaya in Moscow; Writing by Olzhas Auyezov; editing by Stephen Nisbet)