Hosting a keg party soon will become a much dicier proposition in Lawrence.

City commissioners at their meeting Tuesday unanimously approved an ordinance that will allow local law enforcement to more easily charge hosts of keg parties with illegally serving underage drinkers.

Under current state law, in order to charge the host of a party with illegally serving a minor, local law enforcement must prove that the minor was an invited guest of the host.

The new ordinance shifts the burden of proof to the host to show that the minors were not invited guests at the party. The ordinance also would require the host to take reasonable steps — such as checking a picture I.D. — if there’s a suspicion that a minor is trying to drink at a party.

The change in law has been lobbied for by the New Tradition Coalition, a local group that is working to reduce underage drinking in the community.