A former Speaker of the House says Julie Anne Genter's behaviour yesterday was 'dreadful'.

The Green MP crossed the debating chamber last night, confronting Associate Transport Minister Matt Doocey at his seat and waving a booklet in his face.

David Carter says a 2007 scuffle between MPs Trevor Mallard and Tau Henare was outside the chambers.

Carter says Genter could face a range of punishments.

"They could actually expel her from Parliament - unlikely to do that - they could suspend her for a period of time, they could fine her, they could censure her and require her to come back into Parliament with a very fulsome apology."

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