(Updates with details on bonds, U.S. Secret Service comment)

By David Lawder

WASHINGTON, June 19 (Reuters) - A purported $134 billion in U.S. government bearer bond certificates seized by police near the Italian-Swiss border are fake, the U.S. Treasury said on Friday.

"Based on the photograph we've seen online, they are clearly fake. And not even good fakes," said Stephen Meyerhardt, a spokesman for the Treasury's Bureau of the Public Debt.

He added that there is only $105 million in Treasury bearer bond securities outstanding, so the $134 billion amount seized far exceeds the universe of outstanding securites.

The Treasury's determination confirmed the suspicions of Italy's Guardia di Finanza, or tax police, who seized the bond documents in early June from two Japanese nationals at the Chiasso rail station in northern Italy, close to the border with Switzerland.

The bonds comprised 249 "Federal Reserve" bonds of $500 million nominal value each and 10 "Bond Kennedy" with a $1 billion nominal value, the tax police said June 4 in a statement.

A senior tax police officer said Italian authorities also were checking whether the two travelers' Japanese documents are genuine.

In the last two years, Italian authorities have seized some $800 million of U.S. bonds in the Como area in northern Italy.