"You'll get your interest back [in work] and get on with your life."
Problems usually arose when people disliked their jobs or had a stressful holiday period.
Talking about underlying issues and identifying what was making people unhappy could help, he said.
Mental Health Foundation chief executive Judi Clements recommended people ease back into work after their holidays.
While some people made time to recharge over the break, for others the holidays could be quite stressful, with extra responsibilities over Christmas.
"Try thinking about when your next break is so you're not contemplating an endless work period without any break," Ms Clements said.
"For some it might be a good time to think, 'Well, if coming back to work feels so gloomy and awful, is this really the right place for me?' So that kind of reflection can be useful."
Ms Clements said it was important people looked after themselves - getting enough sleep, eating well and exercising.
The blues was a fleeting feeling for most, but those who were still anxious or down after a few weeks should consider talking to their GP.
"It might not just be back-to-work blues - it might be depression or an anxiety state that needs some help."
Auckland University workplace psychology expert Helena Cooper-Thomas said holidays were good for recovering but the effects were "relatively short-lived".
People returning to work should make the most of the good weather and make time for activities they enjoyed, such as exercise, hobbies, gardening or music.
In order to feel engaged at work, people needed to be mentally and physically available, feel safe in the work environment and consider their work meaningful, Dr Cooper-Thomas said.
Some people might not want to return to work because of anxieties about childcare or safety issues, such as an unpleasant workplace environment.
"So they have to consider these factors and they might need to change what they're doing. But otherwise, just try to focus on the good."
