However, he said the election result of about 44 per cent showed it had stood on a strong programme which voters had confidence in.
Bridges also brushed off questions about potential coalition partners for National and its relationship with NZ First and its leader Winston Peters.
Bridges told Newshub those were questions for Peters rather than him – and suggested Peters could pay a price for his attacks on National and decision to side with Labour.
"Frankly, they left us and it is a question for them, not us, about where they stand with that. I think it would be a very limiting factor for them if at the next election all they're saying is they can only go with the Labour Party."
Bridges defeated Peters to win the Tauranga seat in 2008 and described Peters as "a wily customer".
Bridges told Mike Hosking on Newstalk ZB he did not intend to veer from the economic direction National had taken in terms of policy, but would "modernise" other policies, as well as his front bench.
A reshuffle was his first priority and will take place within a fortnight.
He said he expected to keep Judith Collins on his front bench and Steven Joyce would be offered a "strong role".
However, that might not be the finance portfolio he currently holds. He was yet to discuss positions with the senior MPs.
He also said this morning that he did agree with Joyce's election campaign claim that there was a "hole" in Labour's fiscal plan – although he did not necessarily know if it was the $11 billion Joyce claimed.
He did not believe Joyce's credibility had been hurt by that claim, which was debunked by numerous economists.
"I think what Steven Joyce was saying was right. He was making the point that those numbers were very tight."
He said it had shown Labour had left little leeway to pay for the ordinary increases in government spending in areas such as police on top of its own policies.
That would show in Budget 2018.