TOKYO (REUTERS) - Japan aims to boost defence spending over the next five years to help pay for new stealth fighters and other advanced US military equipment, a source with knowledge of the plan said on Tuesday (Dec 11).

The Ministry of Defence will this month present a plan to spend 27 trillion yen (US$239.5 billion) on its military over five years starting from April 2019, said the government source, who declined to identified.

The proposed spending plan, first reported by the Nikkei business daily on Saturday, would see spending rise an average 1.1 per cent per year, exceeding the 0.8 per cent average under the previous plan.

"We still need some more discussion for the final approval," the source said, adding that it would be reviewed by the Cabinet later this month.

Defence Ministry officials were not immediately available to comment.

Some of the new money would be used to buy US-made equipment, including two Aegis Ashore ballistic missile defence radars and Lockheed Martin Co F-35 fighters.

The purchases could help Tokyo ease trade friction with Washington as US President Donald Trump pushes Japan to buy more American goods, including military gear, while threatening to impose tariffs on Japanese auto imports to cut a trade deficit with Tokyo.

The latest military procurement plan will be released with a separate paper outlining Japan's defence priorities over the next 10 years.

Prime Minister Shinzo Abe has been reinforcing Japan's military to respond to any North Korea missile strike and counter China's growing air and sea power in the waters around Japan.