The calls come in the wake of a government pensions White Paper, which sets out future reforms.
The paper's main proposals include the introduction of a system of personal accounts into which employees would be automatically enrolled, as well as employee contributions of 4% and compulsory employer contributions of 3% to be phased in over three years.
A central clearing house as a single point of contact for employers to pay contributions to is also planned.
However, ACS chief executive James Lowman believes the changes will add to retailers' worries. He said: "The ACS has submitted detailed evidence to the government on the impact that the compulsory employer contributions to pensions will have on the local shop sector and this direct cost impact should not be underestimated. Local shops operate in an intensively competitive market where any increase in costs affects the profitability of the business. We have estimated that these costs alone will add more than 1% to employment costs."
Lowman warned that administration and compliance costs could be even higher. "While we welcome a phasing in of employer contributions and not tasking employers to give evidence on which provider to choose, the government has to do more to minimise the cost burden for small businesses."