The tax increase was supposed to take place next year, but now Prime Minister Shinzo Abe wants to delay it to late 2019.

Mr Abe says he wants to speed up his "Abenomics" policy, which aims to reverse more than a decade of deflation and stimulate economic growth.

The sales tax was first introduced in 1989 at a rate of 3%.

"I want to fulfil my responsibility by accelerating Abenomics more and more," Mr Abe told MPs in his ruling Liberal Democratic Party on Wednesday.

The rise in the sales tax from 8% to 10% was initially meant to take place in October 2015, but it was then moved to April 2017 and has now been pushed back even further.

Japan relies heavily on domestic consumption, but its population is ageing and shrinking so fewer people are contributing to the economy.

The Bank of Japan (BOJ) introduced a negative interest rate policy of -0.1% in January, a move which surprised many economists.

The introduction of negative rates - a first for Japan - aimed to increase spending and investment, which should in turn boost economic growth.