Thanks to an increase in counterfeiting of South Korean bank notes, get ready for South Korean paper money that looks different from what you may be used to.

The South Korean government announced recently it would begin issuing newly designed 10,000-won and 1,000-won notes Monday. It already had issued new 5,000-won notes Jan. 2.

But you’ll still be able to use the old money — worth about $10 and $1.

The government is taking the action to thwart what Bank of Korea officials said is a recent increase in counterfeiting, especially of 5,000-won notes.

Those fakes often were a sophisticated product not easily detectable to the unaided eye, bank officials said.

So the South Korean government designed the new crop of notes using high-tech security features.

The move to change the notes also came as South Korean paper money was being criticized as too large and less modern-looking than some other nations’ paper currencies, bank officials said.

Because the new notes are very different in size from the older ones, ATM and vending machine equipment will be modified. The ATMs will need new note identification sensors and deposit boxes, bank officials said.

Unmodified vending machines will be usable with coins only, the officials said.

They asked that anyone who comes across counterfeit money contact the police, the Bank of Korea or the nearest bank and turn it in “to a person in authority.”