Simon Bridges says CGT decision shows his strong leadership

National Party leader Simon Bridges is using the dumping of a capital gains tax to claim a victory for his leadership, while brushing off questions that he may get rolled soon.

"Today is a real win for National under my leadership," Bridges told reporters this afternoon.

Earlier Prime Minister Jacinda Ardern ruled out a capital gains tax after failing to secure the support of NZ First.

She said the Government would pursue other measures - such as making sure multinationals pay their fair share of tax - to make the tax system fairer, but for certainty's sake she said a CGT was now off the table for as long as she was Prime Minister.

Bridges claimed credit for the decision, saying that NZ First would have supported a CGT were it not for National's vocal opposition - a claim quickly rubbished by NZ First leader Winston Peters and Green party co-leader James Shaw.

"We've embarrassed the Government out of a CGT and that is good for New Zealanders," Bridges said.

"In the Government's so-called year of delivery, they've dropped their flagship tax policy.

"The big question remains, what are they doing to encourage the economy to grow?"

Earlier this week Newshub reported that National MPs were losing confidence in Bridges' leadership, citing his handling of the case of the "emotional junior staffer", his falling out with former MP Jami-Lee Ross, and his poor personal polling.

In the latest 1 News Colmar Brunton poll, National had 40 per cent support, but in the preferred Prime Minister vote Bridges only had 5 per cent support - the same as National MP Judith Collins.

Today Bridges repeatedly referred to the axing of a CGT in response to questions about his leadership.

Was he about to get rolled? "No. National supporters right now will be feeling really good, and that's because of my leadership in the National caucus."

Were the numbers were "firming up" for Collins, as Newshub reported? "I'm sure that's not the case. Right now National supporters will be feeling really good about this victory."

Was he refuting caucus rumblings about his leadership? "I'm completely refute anything other than the fact that I'm a strong leader for National."

He would not say whether he had spoken to Collins about the leadership, nor about whispers from National MPs to the media.

"I'm talking with all my colleagues all the time. I feel confident and comfortable in my leadership.

"It's always worth reminding MPs and so on about the need for discipline, but the reality is they know we've had a great win today. They're unified around me.

"I'll be leading this great party right through to the election, and we're planning on winning."

Bridges said the Government killing off a capital gains tax today was a "massive loss" for Ardern, who he said was at the "apex" of her power and still supported a CGT.

"People will be asking questions about that."