October's reading was at the highest pace since December 2013, when the annual pace of deflation also hit 1.7 percent.
Greece's EU-harmonised deflation rate also picked up to a 1.8 percent fall in prices in October from a 1.1 percent drop in September, steeper than a 1 percent decline expected by economists in a Reuters poll.
For years an inflation outlier in the euro zone, Greece has been in deflation mode for the last 20 months as cuts in wages and pensions and a deep recession exert downward pressures.
Deflation in Greece hit its highest level in November 2013, with consumer prices registering a 2.9 percent year-on-year decline.