NEW YORK ( MainStreet) — Open offices are meant to encourage the free flow of ideas and can be great for group collaboration with teammates and managers, but they don't offer much room for privacy. Employees with open offices often find themselves holed up in a conference room or bathroom to take a personal call — or possibly retreating there when a co-worker gets too chatty. Unfortunately, even workspaces with walled-in cubes offer virtually no protection from a determined cubicle invader.

Thankfully, there are strategies to keep visitors at bay and preserve the productivity of your workday. Here are five nice ways to encourage sociable co-workers to pay someone else a visit:

1. Be honest

When you want to be left alone to complete your work, just be honest about that, says Mark Hemmeter, CEO of Office Evolution .

"Don't be passive-aggressive by putting on headphones or leaving a 'do not disturb' sign on your cubicle," Hemmeter says. "The best way to prevent this type of interference from recurring is to be upfront and clear about what you need."

There's no harm in letting your co-worker know, "I have to finish this report before lunch," or "I have to get this done for a client before the end of the day," says Matt Rivera, director of customer solutions for staffing company Yoh.

"It's perfectly acceptable to say you have a call to make or work to do," Rivera says. "After all, you're at work — you're not at a social hour."

If you're worried about hurting your colleague's feelings, you can preface the conversation with a compliment, says Steve Moore, director of human resource operations for HR and business consultancy Insperity.

"Let him or her know that you value the friendship," Moore says. "But that you often get distracted at work and it affects your performance, or forces you to work later hours."

2. Ask them to do you a favor

"This one could backfire, but you can always try asking the person to help you with something," Rivera says. "If you know they're going to stop by unannounced, have something ready they can help you with — something they can take to the mailroom, a fax they could send, or have them help you organize receipts for expenses."

Although asking for favors constantly may deter your cubicle invader from coming around as often, there is a danger they'll feel like you "owe" them something, Rivera cautions.

"They may feel like you owe them a favor because they've helped you, but I think it will probably just make them less inclined to engage you. It only takes once or twice before they're less excited about the conversation that's going to ensue," he says.