New Zealand First leader Winston Peters has warned Grey Power members that NZ Super is under threat - and dismissed Act Party leader David Seymour as Epsom's "ventriloquist dummy".

Peters rounded on Seymour as well as National and Labour in a speech to more than 100 Grey Power North Shore members today.

Covering familiar topics such as the bias of media, immigration levels -  "a fatal pathway to disaster" - and law and order, Peters' central message was that NZ Super was under threat.

"It has been attacked countless times in the past. If anyone thinks it is going to be safe after this election, then they had better think again.

"Don't come to me if [National] win, and they go back on their word."

An ageing population that will live longer has seen some experts call for the age of entitlement to go up.

John Key had said he would quit as prime minister before raising the retirement age of 65. In December, new Prime Minister Bill English said he would not renew that pledge.

Labour in 2014 campaigned on raising the eligibility age, but now leader Andrew Little does not support an increase.

Act Party leader Seymour - who said in a Herald interview this week that Peters was a "charismatic crook" - has called for the age to be raised to 67, matching other countries including Australia.

Today, Peters hit back, to laughter from the audience.

"If you have observed - the number of people saying we can't afford Super, all sorts of economists, all sorts of political parties. Why, there's a ventriloquist dummy in Epsom who says that we can't afford you.

"This is a guy, who alongside [United Future leader] Peter Dunne, their two parties couldn't even get 1 per cent at the last election."

Peters said it was wrong to label NZ Super unaffordable, given immigrants could access the scheme after 10 years.

- NZ Herald