The motion was defeated 57 for and 151 against in the 225-member assembly.
The main opposition United National Party (UNP) blamed the government for connivance in the drug trade which they said had reached alarming levels.
Certain government politicians are behind the drugs trade, it charged.
The government argued that large numbers of detections of attempts to smuggle in drugs into the country had shown that government was keen to tackle the issue.
The government dismissed the motion as politically motivated.