How to layout a page with very long list of sub-navigation items?

We have these few pages that have an inner navigation but for some pages, the number of items is very large. For some pages, the number of navigation items is small.

See below for the ones with a long list of navigation (small white rectangular boxes on the left):

Currently, the items are split into three lines but this looks very cluttered. Is a drop-down a better approach for the pages that have a long list of navigation? Just thinking if there would be a bit of inconsistency because the ones with the short list are listed as a normal navigation but the ones with a long list are listed as a dropdown.

Any better way to approach this?