Shinzo Abe has already pushed back an increase in the domestic consumption tax to 10 percent from 8 percent twice, including in 2016 when he cited global risks such as the Brexit vote that could derail Japan's economy.

However, the premier has more recently affirmed that he intends to stick with the current timeframe to raise the tax rate in October 2019.

He has also pledged to take steps to mitigate any impact on the economy from the tax hike through measures such as tax breaks for durable goods purchases.

"Our basic stance is that we will proceed with the sales tax hike. But it's wrong to be too rigid about this and raise the tax rate no matter what," he told parliament.

Abe said he was committed to the sales tax hike next year but that such a decision could change if the economy was hit by a shock.

"We will proceed with the tax hike unless the economy is hit by a shock of the scale of the collapse of Lehman Brothers" in 2008, he said.

"A Lehman crisis-scale shock would be something like a global economic crisis or a huge earthquake," Abe added.