"If there are no problems during the trial period the council will consider increasing the trial until the end of summer and then permanently," said Mr Munn.
He said Henley Lake was particularly suited as it had good all-weather parking areas as well as toilets and rubbish bins.
"The overseas experience is that even freedom campers stay at a commercial camping ground or motel at least once a week to have hot showers and internet access, so Mawley Park may actually benefit from the freedom camping site," said Mr Munn.
The conditions for the initial trial at Henley Lake prohibits camping on grassed areas, lighting fires, building semi-permanent structures and staying longer than six nights.
However, one Masterton district councillor is angry with the decision made by council officers.
Gary Caffell said officers sent a letter to the development group granting permission to use Henley Lake as a camping site, without any consultation with councillors.
The letter on behalf of the council gives permission for freedom campers to use the grounds on a temporary basis during the Rugby World Cup, which could be extended after the timeframe.
"My anger is based around the fact that the letter was framed by officers without any consultation with councillors, some of whom are known to have reservations about the use of Henley Lake for freedom camping for a variety of reasons, and I have expressed my displeasure to chief executive officer Wes ten Hove," said Mr Caffell.
He said the council should be doing everything they can to encourage people to use Mawley Park, as the council are "pouring huge money" into the facilities.
"My own thoughts are that Henley Lake should not be promoted as a freedom camping site, Rugby World Cup or not," he said.
"Despite regularly using this venue for recreational purposes over many years, I am still struck by the beauty and serenity of the place and I am firmly against anything which could detract from that," said Mr Caffell.
"Allowing freedom campers to camp there, no matter for how long, is, in my view, a big step in the wrong direction."
He said at last month's council meeting the idea was proposed in a report, but there was no definite proposal.
"Had councillors known then what we know now, the discussions would have been considerably more animated and officers would have been instructed how to react, which is the way it should be," said Mr Caffell.