Picking up on a couple of your comments:
The users are employees of a company. They use this website daily to book holidays, download vouchers, find information etc. It will be displayed in the website navigation on an employee intranet/portal.
There will be a "Company Info" menu item with various departments and business things and there will be a "News" item too
It doesn't sound like there's a whole lot else on the main menu. Also, some options are likely to be used far more often than others. For instance, if the "Flexitime" option is about recording when an employee is going to be present for work (or recording when there were present), that sounds like something many employees might need fairly often. And while not every employee will be booking a holiday every day, when they do, they would want the option to be easily found.
With that in mind, it might be worth promoting a few of the most-used options to the main menu (e.g. Company News | Flexitime | Holidays | ...) and leaving the less well-used options behind an overflow menu (perhaps Other Benefits or one of the suggestions from ProtectedLeftTurn's answer).
If you don't already have any data on which options are the most popular, and/or need to be the most visible, then either add some analytics to the existing system or canvass opinion from your employees.