PROVIDENCE — The Rhode Island Division of Taxation has issued notices to more than 100 online retailers, the latest salvo in a growing national battle over collection of state sales tax.

The agency issued the notices to advise the retailers about a new Rhode Island law — dubbed the “Amazon law” — and tell them that they may be obligated to collect the state’s 7-percent sales tax on certain online purchases made by Rhode Islanders, state Tax Administrator David M. Sullivan said on Friday.

Sullivan declined to identify the businesses to whom the notices were sent, but he said they include companies from “a list of the 100 top Internet retailers,” including many well-known names.

“We’re reaching out and doing our part to communicate the change” in state law, Sullivan said in an interview at Rhode Island Division of Taxation headquarters in Providence.

At issue is how the state’s 7-percent sales tax applies to purchases that Rhode Islanders make over the Internet.

In general, a retailer is not obligated to collect the tax on such purchases unless the retailer has some sort of connection to Rhode Island, such as an office, store or warehouse.

But under a new Rhode Island law, a connection is established if the purchase is made through a Rhode Island Web site that is somehow affiliated or associated with the retailer.

For example, the connection is established when someone visiting a Rhode Island Web site clicks on a link to an out-of-state online retailer and makes a purchase.

The provision is the result of legislation introduced by Rep. Steven M. Costantino, D-Providence, chairman of the House Finance Committee, passed by the General Assembly, and signed into law by Governor Carcieri on Tuesday.

Costantino has said that the law is intended to help “level the playing field” for local retailers who collect the tax and are at a competitive disadvantage with online retailers who do not.

Rhode Island’s law is similar to one enacted in New York last year; versions have since been adopted by several states. Because the law affects online retailers such as Amazon.com, it has come to be known as the Amazon law.

In response to Rhode Island’s provision, three online retailers — Amazon.com, Overstock.com and BlueNile.com — severed their links earlier this week with their affiliates or associates in Rhode Island rather than face the requirement to collect Rhode Island sales tax, which they say is unconstitutional.

Rhode Island’s sales tax was enacted in the 1940s under then-Gov. John O. Pastore, said Gary S. Sasse, director of the state Department of Revenue.

Dubbed “a penny for Pastore,” the tax was adopted when “the tax, and our consumption patterns, were linked,” Sasse said. Consumers typically bought goods in local stores, he said.

Nowadays, many purchases are made online. “When the sales tax was invented, there weren’t computers,” Sasse said. As a result, “We have a tax structure that is designed for an economy that no longer exists.”

Rhode Island’s new law is an attempt to reconcile the state’s sales tax to the new economy, he said.

A number of other states are also grappling with the issue.

Some states — including Rhode Island and Vermont – have become parties to the Streamlined Sales and Use Tax Agreement, in which states generally agree to adopt uniform rules involving sales taxes to make it easier for retailers to comply with each state’s sales-tax law.

But Sasse said, “It’s going to be very difficult to resolve these questions in an orderly fashion just at the state level.” Ultimately, the issue could be resolved in the courts or by Congress, he said.

The new law does not affect Rhode Island consumers directly, he said. “This legislation only affects businesses when nexus [in other words, a connection to Rhode Island] is established,” he said.

Even if Rhode Island sales tax is not collected on an online purchase made by a Rhode Islander, the purchaser is still obligated to pay a 7-percent use tax to Rhode Island. But few consumers pay the use tax — either because they don’t know about it, or they are trying, illegally, to save some money.

Patricia A. Thompson, former president of the Rhode Island Society of Certified Public Accountants, said that, overall, Rhode Island’s new law represents “just a reminder that it is every taxpayer’s obligation to pay the use tax on online purchases.”

The decision by some online retailers to sever their ties with their Rhode Island affiliates will have an effect on local businesses, Thompson said.

“It is going to have a negative impact on our Rhode Island businesses — probably small businesses — because they were hooking up with [some online retailers] to expand their market,” Thompson said in an interview at Piccerelli Gilstein & Co. LLP, a CPA firm in Providence, where she is tax partner.

The notice issued by the Rhode Island Division of Taxation, involving the definition of “sales tax retailer,” was mailed to online retailers on Wednesday, said Peter J. McVay, assistant state tax administrator. It is also available on the agency’s Web site: www.tax.ri.gov

ndowning@projo.com