MPs will consider banning foreign donations to political parties after the Security Intelligence Service (SIS) warned that foreign governments want to influence New Zealand politicians.
The SIS also warned the Justice Select Committee that foreign-language news media could be used to persuade expatriate communities to put pressure on MPs.
The committee is considering foreign interference as part of an inquiry into recent general and local elections.
SIS director Rebecca Kitteridge said some "state actors" wanted to influence New Zealand political parties through donations.
"What we know is that there are some states that have got that kind of objective who have been interested in making donations without it being clear where the donations came from," she said.
That posed questions about the transparency and regulation of the system for monitoring and declaring donations to parties, Ms Kitteridge said.
She said the SIS was also worried about foreign influence on foreign-language news media serving expat communities in New Zealand.
Justice Minister Andrew Little said donations from overseas were a real risk.
"It's the risk or the threat that you have significant donations disaggregated and routed through different mechanisms to look like a multiplicity of small donations when in fact it comes from one source," he said.
Mr Little said the select committee was considering what to do to protect against such donations, including whether to ban foreign donations altogether.
He said he was not aware of people in expatriate communities overtly offering donations or support in return for political favours but MPs had to be alert to the possibility.
"Every MP and every candidate during the hustings is always alert to support being tagged to some sort of conditions and most people know once the conversation heads down that path, you get out of it, because the integrity of our system demands that you've got to be beyond reproach."
Green Party MP Golriz Ghahraman said foreign donations should be banned as soon as possible.
She warned that the near-unanimous approval of the ban on semi-automatic rifles this week might not have gone so smoothly if foreign gun lobbyists had started sending money to New Zealand MPs.
"Imagine if that had been the case here. We have just passed our gun laws with so much peace and unity and that wouldn't have been able to happen here so we definitely need to take it seriously," she said.
A member of the Justice Select Committee, the National Party MP Nick Smith said foreign donations should be banned.
He said some ethnic communities had grown a lot in recent years and political parties needed to be inclusive and representative of New Zealand society.
"We want to have a broad democracy in which those new citizens are actively participating in politics, are candidates and are also able to make political donations but at the same time have really robust protections that we're not having money flowing from foreign states or entities attempting to influence," he said.
New Zealand First Leader Winston Peters said foreign governments and businesses had been trying to influence New Zealand politicians for some time.
He said a foreign business once offered him a mind-boggling sum, however, there was no need to ban overseas donations.
"I don't think that if an overseas charity or an overseas entity sees a great cause backed by a New Zealand political party, it doesn't matter which one it is, and says 'look we'd like to give you $1500 to help you in your campaign', I don't think $1500 is going to change the electoral system," he said.
"Let's not throw out everything that's good just because a few people are what I would call, electorally, crooks."
Electoral law states donations over $1500 must be declared and parties are not allowed to keep overseas donations or contributions of more than $1500.