$re = '/^(?:00?|\+)3[3-5]0?|(?!\n)\W/m';
$str = '+331234567
+3301234567
00331234567
003301234567
0331234567
033-123-456-7
0033.1234567';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php