To shore up Japan's declining farm sector, the Liberal Democratic Party on Thursday proposed doubling farmers' incomes over the next 10 years.

Facing criticism for backing Japan's entry into the Trans-Pacific Partnership talks, the LDP is adding this concession to farmers in its campaign platform for the Upper House election in July. Fearing cheap imports, farmers, traditionally a major support base for the LDP, are adamantly opposed to joining the free-trade pact.

In its latest report, the government estimates the sector would lose ¥3.2 trillion if all tariffs are scrapped and cheaper farm products flood the Japanese market.

According to the LDP's 10-year strategy, farmers and their communities would get twice as much as the ¥3 trillion currently doled out. Though still in the planning stages, the goal is to earmark funds for the subsidies from fiscal 2014.

Also on the agenda is achieving a national food self-efficiency rate of 50 percent on a calorie basis by 2020. It was 39 percent in 2011.

As envisioned, a safety net providing basic financial support to farmers regardless of production or market prices, which are volatile, would be introduced.

The government gives rice farmers ¥15,000 per 10 ares, a policy introduced in 2010 by the Democratic Party of Japan, which was then in power. Though the details have yet to be hammered out, the LDP plans to extend the program to other farmers including owners of orchards and grassland.

To encourage larger-scale farming to compete against imports, the LDP also plans to see farmland usage increase from the 50 percent to 80 percent.