Hugh Henry said it is disappointing that police had not been more supportive and that there were inconsistencies in the Scottish Government's approach.
The Labour politician wants to improve legal protection for workers who deal with the publicincludingpost, shop, bus and train staff.
He appeared before Holyrood's economy, energy and tourism committee, stating the case for a Protection of Workers (Scotland) Bill.
Mr Henry, MSP for Paisley South, said: "There seems to be a very clear split of opinion between those who believe that they, and those they represent, will be beneficiaries of this bill on the one hand (and] the legal establishment that believes that there is no need for this."
He said it was "disappointing" to hear police representatives say there is no need for the legislation yet defending similar laws for the emergency services.
Mr Henry said: "The time is right to say to those who serve us that we will do, as politicians, what we think is right to protect them when they're serving the wider public."