\documentclass[a4paper,landscape]{article}
\usepackage[margin=0cm]{geometry}
\usepackage{tikz}
\pagestyle{empty}

\newcommand{\centerlines}{
\begin{tikzpicture}[remember picture, overlay]
  % Vertical center line
  \draw[thin]
    ([xshift=0.5\paperwidth]current page.south west) --
    ([xshift=0.5\paperwidth]current page.north west);

  % Horizontal center line
  \draw[thin]
    ([yshift=0.5\paperheight]current page.south west) --
    ([yshift=0.5\paperheight]current page.south east);
\end{tikzpicture}
}

\begin{document}

% Page 1
\centerlines
\newpage

% Page 2
\centerlines

\end{document}