Prime Minister Bill English is optimistic a Donald Trump presidency will not reverse the recent improvement in New Zealand's relations with the United States but admits a rethink on the Trans Pacific Partnership is needed.

LISTEN ABOVE: PM Bill English speaks to Rachel Smalley 

With just four days until the inauguration of Donald Trump as President of the United States, English said he was not expecting to talk to Trump any time soon.

"They've got to go through this massive process of bedding in a new Government. I'd imagine New Zealand is relatively low on their priorities."

One of Trump's first acts will affect New Zealand's interests - Trump has pledged to initiate the US withdrawal from the Trans Pacific Partnership on his first day in office.

Australian PM Malcolm Turnbull and Japan PM Shinzo Abe met recently to discuss how to salvage the TPP and English said he was not ready to give up altogether either.

"I wouldn't say it is futile, but I think along with those countries, we need to rethink our approach. It could be as soon as next week that the US executes its position and that means we need to rethink it."

He said Turnbull was expected to visit New Zealand in about a month and he would discuss it with him then.

"I would hope there would be a way of keeping the US engaged in the Asia Pacific and the TPP certainly would have done that. There may have to be some adaptation or some other way of doing that."

He said overall relations were very positive, including the first warship visit in 40 years and economic and security ties.

"So we will work with whatever the Trump administration produces. That's what you have to do when you're a small country."

English was speaking in London as part of his trip to Europe to bolster free trade agreement with the EU and a post-Brexit United Kingdom.

"I'm not concerned about being left behind. The Presidential agenda has an important impact on the relationship, but it is not the only component of it.

We will wait and see how the Trump presidency unfolds. But I'm not worried about being caught in the rush.

It will take a lot of time for the administration to settle down. You could spend a lot of time trying to understand what's happening there this week, but in another six weeks it could look different."

He said he had not considered what issues he would raise with Trump at the first meeting. "Simply because it looks like it will be some time before we will be in a position to raise those issues."

- NZ Herald