GIBRALTAR — Since Spain introduced tighter border checks as part of a tit-for-tat feud over the sovereignty of this British territory at the tip of Spain, Lola Ballesteros Benítez’s commute has become a lot harder.

To avoid sometimes hourlong waits at the crossing, Ms. Ballesteros Benítez, an assistant nurse who lives in the Spanish port city of Algeciras but works in Gibraltar, has been parking her car nearby and walking across the border, before taking a bus. When she works nights, and the buses do not run, she takes a taxi, adding to her costs. What used to be a 45-minute commute is now a journey of at least two hours, she said.

“I don’t think the government in Madrid realizes just how much harm can be done to some of its own citizens,” she said.

Indeed, the dispute among Spain, Britain and Gibraltar has threatened an economic lifeline for Ms. Ballesteros Benítez and about 7,000 other Spaniards who cross the border daily to work within the confines of this 2.6-square-mile promontory — dominated by the Rock of Gibraltar — where the economy grew 8 percent last year. It is one of the few places in Europe to have emerged unscathed from the financial crisis.