# Insert empty pages until certain page number

I have sections which have to start exactly at the predefined page numbers and the potentially unfilled pages between these sections should be filled with empty pages. Is there a for-loop available that would insert \newpage until the right page where the new section starts is reached?

Without any package, you can do with \loop; the trick is to add something invisible to the empty pages, for instance \null (more efficient than \mbox{}):

\documentclass{article}

\newcommand{\filluptopage}[1]{%
\clearpage
\loop\ifnum\value{page}<#1\relax
\null\clearpage
\repeat
}

\begin{document}
Page 1 has text.

\filluptopage{5}

This will be at page 5.
\end{document}