It is currently at 0.2 percent, a trend that has prompted the ECB to start buying 60 billion euros worth of assets a month, mainly sovereign bonds, to combat deflation.
"There should be no ambiguity on the willingness and ability of the governing council to act if needed," Praet, said. "The (asset-buying program) provides sufficient flexibility to do so in terms of size, composition and length of the program."
The bank has already warned that financial developments in China could have a larger-than-expected adverse impact given Beijing's prominent role in global trade. China's growth outlook has declined sharply in recent weeks, potentially increasing the risk for Europe.
The ECB targets inflation at just under 2 percent and last forecast price growth at 1.8 in 2017 but key inflation drivers have worked against it since the June projection.
Crude oil prices have fallen close to 40 percent since May while iron ore price are near historic lows on expectations that Chinese growth will continue to slow, hitting its lowest level in two decades.
The 5-year/5-year swap rate, ECB President Mario Draghi's preferred measure of judging inflation expectations, fell below 1.4 percent this week before rebounding to 1.6 percent on Wednesday. Another swap rate has suggested deflation in year's time.
The pan-European FTSEurofirst 300 index pared losses of nearly 3 percent on Praet's comments, later trading down around 0.8 percent.