Japanese Prime Minister Shinzo Abe's grand plan to revive the economy, which has run into several stumbling blocks in the past year, is reaching a "moment of reckoning", Goldman Sachs has warned.

There are several key turning points before the year-end that will be key in determining whether Abenomics will succeed or stumble, according to the bank, pointing to this week's cabinet reshuffle, a potential expansion of the Bank of Japan's (BOJ) aggressive easing program, and a decision on whether to move forward with a second tax hike in 2015.