TOKYO, July 2 (Reuters) - Japanese government bond (JGB)

yields extended their rise on Thursday as a weak auction of

10-year bonds highlighted investor concerns about heavier

government spending.

Here are a few details:

* The benchmark 10-year JGB yield rose 4.5

basis points (bps) to 2.745%, its highest since May 22. Yields

move inversely to bond prices.

* The 30-year yield rose 4.5 bps to 4% ahead

of an auction of that maturity next week.

* "The 10-year bond auction was weak given the widening

tail," said Masahito Sugawara, a senior strategist at Daiwa

Securities.

* The auction's tail, or the gap between the lowest accepted

price and the average price, widened to 0.2 point from 0.05

point at the previous auction in June, indicating weaker demand.

* "Investors are concerned if the government's big spending

plan would bring future economic growth," said Sugawara.

* In its growth plan, Japan will seek to work with the

private sector to channel resources into strategic industries,

with combined public and private investment projected to exceed

370 trillion yen ($2.28 trillion) through fiscal 2040.

* The five-year yield rose 1.5 bps to 1.925%.

($1 = 162.5200 yen)

(Reporting by Junko Fujita; Editing by Subhranshu Sahu)