A former CIA agent who became an important arms broker in the Iran-Contra scandal was sentenced by a federal judge to 16 months in prison on income tax charges.

Thomas G. Clines, 62, of Middleburg, Va., was convicted Sept. 18 on two counts of making false statements on his 1985 and 1986 income tax returns and two counts of failing to report foreign financial accounts to the Internal Revenue Service.He faced up to 16 years in prison and $1 million in fines for the four counts when he was sentenced Thursday by U.S. District Judge Norman Ramsey.

Ramsey also fined Clines $40,000 and ordered him to pay the cost of his prosecution, which has yet to be determined. His lawyers have 10 days to appeal.

Clines became the eighth person convicted in connection with the secret Reagan administration plan to sell weapons to Iran to win freedom for U.S. hostages and divert the profits to the Nicaraguan Contra rebels at a time when such aid was banned by Congress.

Although he lives in Virginia, Clines was charged in Maryland because his tax preparer is from Bethesda.

During his 11-day trial, prosecutors told jurors how Clines created an elaborate system, including the use of a safe deposit box in Geneva, to collect some $900,000 in profits from the arms sales he helped broker.