I can access @ARGV from a sub in a package from a separate script:

$ cat Foo.pm 
package Foo;

sub p { print "@ARGV\n" }

1;
$ 
$ cat foo.pl
#!/usr/bin/env perl

use Foo;
Foo::p();

$ ./foo.pl abc 123
abc 123
$
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Do you get errors or warnings? Show your code and how you call it.