TVNZ's news and current affairs boss Anthony Flannery said Harcourt had been treated by a doctor following the attack and was told to avoid flying.
"He is remarkably upbeat despite having never been the victim of an assault before," said Flannery.
He described the incident as "deeply concerning", but added such attacks were extremely rare.
"Occasionally, Fair Go crews are jostled and threatened while filming, but rarely has anyone been physically assaulted in the programme's 34-year history.
"Security routinely accompanies Fair Go on jobs where confrontation is possible. Gordon's trip to Mt Maunganui on Friday was not considered to be one of those situations."
A cameraman who was filming with Harcourt was unhurt during the incident, which occurred about 3.30pm.
TVNZ was still determining damage to camera equipment. It was hoped that footage could be retrieved to form part of the police evidence against the car dealer.
Detective Sergeant Darryl Brazier, head of Mt Maunganui CIB, said police were still investigating the incident.
Former Fair Go presenter Kevin Milne said he was appalled but not surprised that his friend had been attacked.
"I think the scary thing about working for Fair Go is that the attacks come from the most unlikely quarters. We did come across some nasty characters, a guy threatened to bomb my house once."
Milne said the rule when confronted during filming was to "keep the cameras rolling".
"I'm sure Gordie will be hoping that it was all captured on film."
The car dealer has already featured in a Fair Go piece.
Harcourt exposed the caryard for offering $800 for a "repo-ed wreck" which it later put back on the lot for $7000.
According to Fair Go, the caryard's target market is low-income people, attracted by no-deposit terms and cheap weekly payments.
"Beneficiaries welcome" says the marketing.
The company director also runs a finance company that offered rates as high as 30 per cent.
Harcourt has appeared on TV screens since 1989.
In 2001 he moved to the UK and worked for the BBC and as a London correspondent for TVNZ, before returning to work for Fair Go in 2008.