A SEIL spokesperson said it had informed the Bangladesh authorities about what it called an "unsustainable situation".
Bangladesh, which imports nearly 20% of its power from its neighbour India, has not paid for the electricity for the last eight to nine months, a source told Reuters.
SEIL received a contract in 2018 from BPDB to supply power to Bangladesh over a total period of 15 years.
"While we continue to supply power to Bangladesh, we remain hopeful the concerned authorities will uphold the contractual terms and expedite the clearing of the dues, so that power supply can be sustained," SEIL said in a statement.
SEIL and PTC India have bank guarantees relating to their power contracts with Bangladesh for $34.1 mln and $30.7 million, respectively, the documents show.
This has left Bangladesh's Rupali Bank trying to access dollars to settle payment of about $270 million, as otherwise the Indian companies plan to cash the guarantees.
Rupali Bank and BPDB are working "together for the necessary U.S. dollar resources from (the) Bangladesh Central Bank for the purpose of paying bills in foreign currency, which will continue in the future," the documents show.
PTC India declined to comment on the specifics of terms and conditions of the contract, while calls to Rupali Bank went unanswered due to a weekend holiday in Bangladesh.