Tokyo stocks will likely maintain their upward momentum in 2015 largely thanks to the weakening yen, which sharpens Japan Inc.'s competitive edge.

Wage hikes urged by Prime Minister Shinzo Abe and the possibility of additional monetary easing by the Bank of Japan are also expected to support the stock market, although an interest rate hike in the United States could trigger a correction, economists and brokers said.

The benchmark Nikkei 225 stock average is forecast to end up between 18,000 to 20,000 at year's end, with some even projecting it to hit 21,000. The Nikkei finished 2014 at 17,450.77, its highest year-end close in 15 years.