Prices fell 0.7% in March, matching the largest one-month drop since 2008.
When prices drop, consumers may start to put off buying things now in hopes of paying less in the future.
The ONS said it would monitor the issue for any distortion in the overall picture.
It came as gas prices fell by 39.3%, Statistics Canada said.
Food, however, increased in price by 3.4%, while cleaning products surged 4.6%.
The National Bureau of Statistics (NBS) disclosed this yesterday in its Consumer Price Index (CPI) Report for April 2020.
Takeshi Minami, chief economist at the Norinchukin Research Institute, said prices related to services and private consumption reflected the impact of the virus in April when a nationwide state of emergency was declared, under which people were asked to refrain from nonessential outings.
The ONS said clothes retailers, hit during the early days of the lockdown by weaker footfall and then the closure of outlets, resorted to more discount sales than usual to try to shift their stock.
Pints of beer and cinema popcorn removed from inflation basket during lockdown
The average of Canada's three measures for core inflation, which are considered better gauges of underlying price pressures and closely tracked by the Bank of Canada, was 1.8 per cent year-over-year.
The reading may fuel speculation more action is needed, and may intensify an emerging debate among policy makers over the case for eventually taking rates below zero for the first time. "Inflation dropping to a four-year low is good news to savers, for now at least, but savings rates are still being cut across the market", she added.
Low inflation minimises the erosion of debt over the years.
The federal government had on May 2, 2020, directed the release of about 17,500 metric tonnes of assorted grains from the Yola National Food Reserve site for distribution as palliatives to Nigerians. Low inflation generally means lower official interest rates - and that means banks and building societies keep their savings rates down.
The data highlights the challenge the Bank of Japan faces amid the ongoing coronavirus pandemic to achieve its elusive 2% inflation target.
"Inflation should be the least of our worry; it should be trying to exit the lockdown, and getting the economy to recover".
"With the economy likely still underperforming if and when further restrictions are lifted, there will be an underlying drag on inflation that central bankers will need to offset with additional monetary easing", Royce Mendes, an economist at Canadian Imperial Bank of Commerce, said in a note to investors.
Osaka tops Serena as world's highest-paid female athlete
She has won about $14.5 million in career prize money, according to the WTA, a little less than half of which was earned in 2019. Nike signed an apparel deal with Osaka last year that paid her $10 million in the past year and runs through 2025.
Coronavirus Survivor Shares Shocking Body Transformation Pics
He is now on the road to recovery and planning to get his body back "in healthier ways this time". "Maybe (I'll) even do cardio". Schultz is one of 38 people believed to have gotten sick from the virus after attending the Winter Party Festival in Miami .