use strict;
use Data::Dumper;

my %hoa;
while(<DATA>) {
    chomp;
    my($k, $v) =   split /\s*:\s*/ => $_, 2;
    $hoa{$k}   = [ split ';'    => $v ];
}
print Dumper(\%hoa);

__DATA__
t-98: 12;3;56;24
t-56: 1;98
t-3 : 12;56