Keeping the Federal Reserve's latest stimulus efforts open-ended lowers the bar for stopping the program if inflation pressures should emerge and become destabilizing, Richmond Fed President Jeffrey Lacker said on Tuesday.

The Fed last week launched an aggressive new effort to energize the economy, saying it would buy $40 billion a month in mortgage-backed securities until it sees a sustained upturn in the weak jobs market.

The open-ended flexibility was a "positive feature," said Lacker, who was the lone dissenter against the decision.

(Reporting by Leah Schnurr; Editing by Leslie Adler)