"Inflation is still a problem for us, as it is for many countries," Lee said in a televised address ahead of Singapore's national day on Wednesday.
Headline inflation in Singapore slowed to 4.7% in May compared to 5.4% recorded in the first quarter.
Monetary Authority of Singapore chief Ravi Menon said last month that Singapore's inflation would ease significantly thanks to a tight monetary policy stance, but the central bank would "not switch from inflation-fighting mode to growth-supporting mode".
PM Lee on Tuesday also addressed a recent spate of scandals, including a graft investigation involving a minister and the resignations of two senior lawmakers including the speaker of the house. The cases have shocked the country that has a reputation for squeaky-clean politics.
"Let there be no doubt: my government is determined to keep our system free of corruption and wrongdoing," he said.
