Simon Bridges wants a full, independent investigation into who leaked his travel costs.
Speaker of the House Trevor Mallard is deciding whether that's warranted.
Bridges says he's very confident it's not a National MP.
Only National's caucus, Parliamentary Services and the Speaker had access to the file.
Bridges told Mike Hosking it's not so much about the costs - which were due to be released tomorrow anyway - but the integrity of parliament.
"I want to get to the bottom of actually whats gone on with a Government that wants to distract from the issues that everyone should be focused on, so let's get to the bottom of it."
Jacinda Ardern confirmed yesterday that no Labour MP or minister should have had any access to National's expenses.
LISTEN TO SIMON BRIDGES TALK WITH MIKE HOSKING ABOVE
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