Judith Collins has praised the Government's decision to rule out future regional fuel taxes.
But she's questioning why Aucklanders have been hit with the 11.5c a litre charge.
The Government changed the law in June to allow Auckland Council to put extra charges on fuel. While the legislation says other regions can't do the same until 2021, Prime Minister Jacinda Ardern on Wednesday announced none will be allowed to while she's Prime Minister.
"It's a good decision that she's done that," Ms Collins told The AM Show on Friday. "So how come Auckland is treated differently from everyone else?"
Labour MP Michael Wood, appearing on The AM Show alongside Ms Collins, said it's because Auckland needs more funding to fix its awful traffic problems.
"It was neglected for nine years, he said, referring to the previous Government's time in office. "Total chaos."
Ms Ardern's announcement no other councils would be allowed to implement regional fuel taxes while she's Prime Minister took some by surprise. Asked in Parliament when he knew of the policy, Associate Transport Minister Shane Jones said, "When the Prime Minister stood up."
"What we're seeing from Prime Minister Ardern is she does have a tendency to make policy up on the hoof," said Ms Collins.
"We saw it with the oil and gas decision, which officials found out about 7:30pm the night before she announced it to the world. We're seeing it with the regional fuel taxes. I have to say if we weren't going to have them, how come you changed the law to make it happen?"
There have also been claims the Government had discussions with local government authorities about potential fuel taxes in their areas, which the Government has denied.
Mr Wood said the law which made regional fuel taxes possible, passed in June, made that clear.
"The law said that they literally couldn't happen for at least three years anyway, so there was no regional fuel tax on the table for anyone else. We've had a whole lot of speculation and some incorrect things being said in the media. What the Prime Minister's done is provided some certainty there won't be."
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He called it "strong and decisive" leadership, adding that Ms Collins has the same attributes. The controversial former National leadership candidate recently polled narrowly behind Simon Bridges in a preferred Prime Minister poll.
"We're all very pleased for Judith. She's strong and decisive, and I think people in National are looking for that," said Mr Wood.
Ms Collins was just happy to have polled ahead of Winston Peters, and put her success down to regular appearances on The AM Show.