The Prime Minister's links with lobbyist Gordonjon Thompson [GJ], whose clients include Huawei, "just happens to be a case of New Zealand being small", she said.
Newsroom reported this week questions had been raised over Ms Ardern's relationship with Mr Thompson, after he was her chief of staff for five months while the current Government was forming after the 2017 election.
His consultancy company, Thompson Lewis, counts Huawei as a client.
Chinese company Huawei's bid to assist in developing New Zealand's 5G network was denied by the GCSB in November last year.
Ms Ardern said Mr Thompson had been a friend of 14 years and the pair did not discuss his clients.
"This just happens to be a case of New Zealand being small and I have an old friend who works in his own company.
"I already know that GJ works alongside companies external to Government. I don't know, by in large, what those companies are."
She said Huawei was "not even a company I had any familiarity he was working with".
Ms Ardern said there was "plenty of transparency" in Government.
"New Zealand is a small country, there will from time to time be overlap. The important thing is that we manage ourselves those conflicts. I do not discuss... nor does he discuss with me, his clients' issues. That would be totally inappropriate."