A government consultation running until 25 August will shape how new rights on guaranteed hours, shift notice and compensation for cancelled or cut-short shifts are put into practice.
ACS said the reforms must not add complexity or unintended costs for retailers already under pressure from higher business taxes, tighter regulation and a tight labour market.
The trade body argued many convenience retailers already offer two-sided flexibility: 96% of colleagues are on permanent contracts, more than three-quarters say they have never had a shift cancelled, and one in three has stayed over 10 years.
ACS said it supports tackling one-sided flexibility but wants implementation of the Employment Rights Act to stay pro-worker and pro-business, warning poorly designed rules could reduce flexible job opportunities.