TOKYO, Sept 24 (Reuters) - Japan's Prime Minister Shinzo Abe will announce a plan to raise gross domestic product to 600 trillion Japanese yen ($5 trillion) as he shifts his focus back to economic policy, national broadcaster NHK reported on Thursday.

The government will focus on steps to expand incomes, support childcare and nursing for the elderly, NHK said without citing sources. Abe will reveal the plan at a news conference on Thursday marking his election to a second three-year term, NHK said.

The GDP target could draw criticism for being unrealistic because it implies levels of growth not seen in the last two decades.

In fiscal 2014, nominal GDP was 491 trillion yen, so the economy would have to expand by 22 percent to reach the 600 trillion yen mark. Since fiscal 1994, the earliest date that data are available, Japan's nominal GDP has actually contracted by 1 percent.

Since Abe took office in late 2012, nominal GDP has expanded 5.8 percent as the central bank pursued quantitative easing, and a stock market rally encouraged some individual investors to increase consumer spending.

After an initial wave of success, investors have grown disappointed with the scale of Abe's structural economic reforms.

Cabinet ministers have recently said that Abe will also target increases in capital expenditure as he tries to breathe new life into his economic agenda.

($1 = 120.2700 yen) (Reporting by Stanley White; Editing by Eric Meijer)