Ramonas is charged with abuse of powers and could face a fine or up to five years in prison, if found guilty.
Prosecutors suspect that Ramonas' actions led to a delay in the establishment of the true financial situation of Snoras and identification of its potential insolvency and incapacity to meet reasonable financial demands of its creditors.
Ramonas was sacked in late November 2011, having headed the banking supervision department for 15 years, since March 1996. He was employed at the central bank for a total of 19 years.
Prosecutors are currently performing a separate investigation into Snoras' bookkeeping fraud, document forgery, abuse, property embezzlement, and money laundering.
Suspects in the case include Snoras' main shareholder Vladimir Antonov and board chairman Raimondas Baranauskas. Their extradition to Lithuania is to be decided by a London court.
The Lithuanian government nationalized Snoras in November 2011.