National hasn't changed its mind on the scope of its support for Act's Treaty principles bill

Act Leader David Seymour wants to introduce the legislation by May.

National has promised to support it up to select committee stage, but Seymour says it hasn't ruled out further support.

But Maori Development Minister Tama Potaka says National will keep to the letter of its coalition agreement.

He says Seymour is entitled to have his opinion, but it won't go further than the first reading.