TOKYO, July 14 (Reuters) - Yields on benchmark Japanese

government bonds (JGBs) jumped to a seven-week high on Monday,

as concerns grew that an upcoming election would lead to more

fiscal expansion.

Prices for super-long-dated bonds sank last week, driving

yields sharply higher, as prospects dimmed that Prime Minister

Shigeru Ishiba's ruling coalition will retain its majority in

the upper house after a vote on July 20.

The potential defeat could give power to opposition parties

that have pledged in their campaign platforms to cut or abolish

the sales tax. Fiscal concerns and a drop in demand at debt

auctions triggered a surge in super-long yields to record levels

in late May. The Ministry of Finance this month trimmed its

issuance of super-long JGBs in response.

The 10-year JGB yield rose 5 basis points

(bps) to 1.55%, its highest since May 23.

The two-year yield rose 1.5 bps to 0.775%,

while the five-year yield rose 2.5 bps to 1.055%.

Super-long JGB yields were unchanged in early trading.