National has reversed its position on supporting senior Donald Trump staffer Chris Liddell for the OECD's top job, saying his ties to the outgoing President "cannot be overlooked".

In a statement, leader Judith Collins was scathing in her assessment of Liddell – who is a New Zealander.

"The rioting that took place in the US Capitol was a disgraceful attack on democracy that has rightly tarnished those who incited and enabled the violence," she said.

"Mr Liddell's ties to the Trump Administration cannot be overlooked here, making it difficult to see how he would be suitable to uphold the OECD's strong commitment to democracy."

In November last year, she was striking a markedly different tone when throwing her support behind Liddell becoming the OECD's Secretary-General.

"He's going to work more in New Zealand's interests than anyone else who will be up for that job," she told RNZ at the time.

She said that before he went to work at the White House, Liddell was a very experienced and well-regarded businessman.

During the interview, she distanced Liddell from Trump's record and his opposition to multilateral trade deals.

"The fact is it wasn't Mr Liddell's administration – he was working for it."

She said National had a record of supporting New Zealanders when they were up for top international jobs, such as leading the OECD.

But the events of last week, and Liddell's involvement by association, have clearly changed Collins' mind.

National's withdrawal of support from Liddell comes after Act did the same thing.

"Following Mr Liddell's failure to denounce recent events, Act can no longer support him in his candidacy," the party's deputy leader Brook van Velden told Newshub.

Liddell – who has been described as Trump's right-hand man – finishes up in the While House later this month.

After last week's riots, a number of senior Trump staff resigned but Liddell said he would stay on until the end as it was the right thing for the country.

He told the Herald he was "horrified, like everyone else," by Capitol riots last week.
In October, a spokesman for Prime Minister Jacinda Ardern said the nominations for OECD's Secretary-General had not yet closed.

"The Government is yet to make a decision on which candidate it will be supporting," the spokesman said at the time.