Former Southland MP Barclay allegedly made clandestine recordings of a staff member he suspected was critical of him. The revelations led to him announcing he would not stand for re-election.
Peters went on in his speech to call the National Government "Robin Hood" in reverse - taking off the poor to give to the rich, many of whom are foreigners.
"They want to know why as working men and women they are so damn poor, and why so many 'shiny bums' in Wellington are not doing anything to help them."
He also called out a number of National MPs by name, for being untrustworthy, and said English was "brazenly trying to con the public".
"Bill English goes around boasting that people want to come to New Zealand because we are a growing economy. Much of the world is a hell hole. Talk about post-truth politics."
He questioned when New Zealanders last felt they could actually trust a National MP.
"Where trust is unreserved and you are glad you know that person.
"Tell me, did you ever feel that way about John Key, Bill English, 'Mr Fixit' Steven Joyce or Judith Collins, or Paula Bennett or Nick Smith or Simon Bridges?
"Trust has to be earned."
Peters' criticism covered many of the National Government's people and policies and even made comparisons between it and the Titanic.
"Political stability will be what the National Party tries to argue in this election that they represent. Well, the world's most stable, unsinkable ship was the Titanic, until it sank. "
He questioned the stability of Nick Smith's housing policy, pointing out what he saw as the instability of people's freedom to be secure in our homes, businesses and on our streets.
Peters said the last Government had left police "short-handed everywhere", a society where he said people had to prove they were suicidal before being given access to the "little services" available for those with mental health issues.
"What is stable about an economy when over 130,000 can't even get one hour's work, when 92,000 young people aren't in education, training or employment? Where another 100,000 are seeking more work hours?"
He said there was also nothing stable about an economy that had the most "volatile" currency in the "whole wide world".
Peters went on to say an economy where imports exceeded exports, manufacturing was on the decline and home ownership was at its lowest point in 63 years - down by 38 per cent when it came to Maori home ownership - was the very opposite of stability.
The NZ First Party leader said there was also rampant instability in a health system where GPs worked through their lunch breaks and an education system that saw kids packed into "libraries, corridors or worse" for their lessons and more students leaving with debt and no job.
In his speech Peters said it was time for a "political upset".
"They [New Zealanders] want someone not afraid to speak out and say the things that need to be said and do the things that need to be done. They want someone to keep other parties honest, who actually cares about New Zealand."
The party leader said there had been too many governments of late that "haven't been straight with Kiwis" and too many parties that were "simply out of touch".
Only time will tell just who Peters thinks would be best placed to drive this "political upset" to achieve what he thinks the country needs.
National, Labour and the Greens are all spending the week preparing for what could be gruelling coalition negotiations with New Zealand First - and if Peters stands by these comments, it could seem as if National is on the back foot.
On the basis of policies National already seems to have less in common with NZ First's preferred policies. Only three seem to align, compared to Labour's nine.
The priority afforded to each policy could also be more indicative of which way NZ First could lean as opposed to numbers alone.
