Work was being done to register the NZ Independent Coalition as a party entity and he hoped to be position to do so within six weeks, he said.
"I have had approaches from a number of people who are keen and willing to stand under this entity, not just independent MPs, and I will have no problem in registering 500 members."
Mr Horan said an independent MPs' coalition would change the political system landscape, because it would make MPs "truly accountable and transparent".
Since his time in Parliament, Mr Horan said he had seen a number of disenchanted MPs who were not able to serve their communities the way they wanted to.
Governance under the coalition would be by majority vote and agreement in terms of major confidence and supply issues, but coalition MP members would still be able to vote in Parliament on what they believed was best for their area, he said.
"It also gives people a greater voice and empowers New Zealanders to participate in the democratic system throughout the entire parliamentary term, not just at election time."
Most importantly, people can have their say on issues, rather than MPs saying they were going to do one thing and once they get into office they do something entirely different.
Mr Horan said registering a coalition political entity made sense as it meant there would be access to funding and more parliamentary resources.
Coalition MPs could also support each other.
Mr Horan said anyone would be free to join, even if they were involved with other parties.
"But to become a candidate, we would adopt the same process Justices of the Peace have to go through, whereby they need to be recommended by at least two different community groups."
Tauranga JP Michael O'Neill, who is also president of the Tauranga Justices of the Peace Association, said he was in favour of the coalition proposal.
"The time for party politics in New Zealand has done its day and many people believe the time has come to try something fresh and different," he said.
Mr O'Neill, who was first runner-up for one of the five Tauranga general constituency seats at 2013 Bay of Plenty Regional Council elections, said there was already successful coalition model working within regional council.
National MPs Simon Bridges and Tony Ryall could not be contacted for comment.