Security guards reached a tentative contract agreement on Thursday with their employer Securitas after a week of heated discussions during which guards said they would go on strike if they were not allowed retain their union health care plan.

Leaders within SEIU Local 615, the union which represents Harvard security guards, said that they were very pleased with the five-year agreement, which stipulated a 15.3 percent wage increase over five years, an increased number of full-time jobs, and protection of their current health care coverage.

“I think the company and the union see this as an initial step towards a more cooperative and mutually beneficial relationship in the future,” Wayne M. Langley, the director of higher education for Local 615, said.

Securitas did not return calls for comment. The University does not comment on negotiations with Securitas.

The negotiations started off smoothly but took a rocky turn when Securitas introduced a proposal that would have reduced health care benefits, which proved to be the sticking point in talks between SEIU and the security firm.

Security guards were outraged at the proposal, which would have stripped them of their union health care plan, and began circulating a petition expressing willingness to strike over the new health care provisions. Over 80 percent of security guards signed the petition, which was formally presented to the bargaining committee on Monday.

Now that the threat of a strike has passed, Wayne M. Langley, the director of higher education for Local 615, said he is hopeful that this will mark the beginning of calmer relations between the union and Securitas.

“In the end, both parties put aside our differences and did what was right for the guards,” Langley said.

Security guards will formally vote to ratify the contract on Wednesday.

Securitas guards said that they were excited that their bargaining committee agreed upon a contract and relieved that a strike had been averted.

“I’m very happy that an agreement’s been reached,” said security guard Shawn Lynch. “Everybody wants to have a peaceful work environment. You want to feel supported by your employer.”

While Lynch said that he will not know the specifics of the contract until the union meets on Wednesday, he is confident that it will be satisfactory.

“I have full confidence in our bargaining committee,” Lynch said. “They’ve worked hard for us.”

Student labor activist William P. Whitham ’14, a member of Student Labor Action Movement, said he was happy that a strike had been averted and that the two parties were able come to an agreement.

“Security guards are obviously a very important part of this institution. It would be very bad if they were not around,” Whitham said. “I’m glad they were willing to strike, but I would rather see a fair, just compromise be reached.”

Whitham said that the current contract agreement, coupled with the agreement Harvard has with dining hall workers, reflects well on the University.

“Like with the dining hall workers, it says a lot about our institution that it treats its workers fairly,” he said.

—Staff writer Mercer R. Cook can be reached at mcook@college.harvard.edu.