Darij Krajcic, a member of parliament for the Marjan Sarec List (LMS) party -- the senior partner in the ruling coalition -- said he walked off without paying because three supermarket employees had “treated (him) like air” and continued chatting.
“I must have stood some three minutes by the counter,” he told private POP TV.
Krajcic insisted that he returned shortly afterwards to pay for the sandwich.
But he apologised and resigned from parliament.
The centre-left LMS party of Prime Minister Marjan Sarec is the senior member of a five-party minority government, voted in last September.
Public support for the premier has received a boost recently from public sector wage hikes and the dismissal of two ministers accused of abuse of power and bullying.
The head of LMS’ parliamentary faction, Brane Golubovic, condemned Krajcic’s actions as “unacceptable” and said the MP “has to bear the responsibility, in line with LMS’ high ethical standards”.