Tougher drinking conditions will be enforced in Northbridge nightspots later this month in a bid to reduce the alcohol-fuelled violence in late-night venues.

Effective from May 23, no liquor is to be mixed with energy drinks and no unadulterated spirits or shots can be served after midnight.

Northbridge drinkers will soon be subject to stricter alcohol laws.

After 1am, no drink can be served in a glass larger than 750ml, pre-mixed drinks can't be served in glasses half that size and no more than 50mls of spirits are permitted in any single drink.

Patrons also can't enter, or re-enter any licensed premises within half an hour of the closing time.