A business offensive recently launched in Thousand Oaks by national chain Dollar Tree is driving out its next door competitor, locally-owned Dollar Store Plus.

Dollar Store Plus has operated in the Park Oaks Shopping Center at Janss and Moorpark roads since 2003 but is moving to a new Thousand Oaks location because Dollar Tree has set up shop on the other side of an adjoining wall.

Already trying to survive in an ailing economy, Dollar Store Plus had its business drop off sharply since its new neighbor moved in around Thanksgiving.

Dollar Store Plus owner Amy Kazmie of Thousand Oaks is upset with her landlord, Los Angeles-based Decron Properties, which owns the shopping center. Decron did not return two calls to comment for this story.

Kazmie is weighing her legal options, contending that Decron did not act in good faith by allowing Dollar Tree to move in next door.

Both shops offer similar $1 items, but Dollar Store Plus is a much smaller operation than its national competitor that operates more than 3,500 stores in 48 states.

“We’re supposed to be acting in each other’s best interests,” Kazmie said of Decron. “Yet they put in a direct competitor directly next door to me, three times the size with national name recognition.

“It’s ... negatively impacted us,” she said. “I stand outside and watch my customers walk in there. Competition in business is the name of the game. But it should be fair competition. This is completely unfair competition.”

Kazmie said the building Dollar Tree moved into was vacant for four years.

Shelly Davis, a spokeswoman for Chesapeake, Va.-based Dollar Tree, declined to discuss the chain’s decision to move in, other than to issue a brief statement: “Dollar Tree is excited about being in the Thousand Oaks community.”

Gary Wartik, economic development manager for the city of Thousand Oaks, said having two similar businesses directly next to each other “is actually very unusual.”

“One would have to ask the lessor why that’s occurring,” he said.

The city of Thousand Oaks takes a hands off approach to such leasing disputes.

“The leasing process is strictly private sector to private sector,” Wartik said. “It is not a city function.

“If party A wants to move in next door to party B and they’re competitors, our view is that that’s part of the free market, that competition is good for business and the consumer is the ultimate beneficiary with better choices, perhaps better pricing,” Wartik said. “That has always worked well, and it will continue to work well, notwithstanding the fact that we’re in a recession.”

Kazmie said the last time she negotiated her lease with Decron, she asked for a clause that would make her business the exclusive dollar store in the shopping center.

“And for whatever reason, it didn’t get put into the lease,” she said.

Last June, Kazmie said she learned through a maintenance worker that Dollar Tree was moving in next door. She then decided not to renew her lease, which expired at the end of December.

After Dollar Tree moved in, Kazmie fought back by lowering all $1 items to 90 cents and posting a sign that emphasized her store has been “locally owned since 2003.”

But her sales plummeted 60 percent to 70 percent from the previous year.

She plans to move her store at the end of January, but she declined to provide an address until the business is actually in a building.

“It’s like starting over,” Kazmie said. “It really is.”