The Ministry of Business, Innovation & Employment ran a free mediation service which "nine times out of 10" was attended by local employers and workers to try and settle their disputes, Mr Parker said.
"The lion's share of those are resolved because the costs involved in going through are significant."
Most disputes arose from unjustified dismissals, he said.
Earlier this month, a Nelson rest home worker dismissed after hiding behind a door when discovered with a gardener in a dead resident's flat was awarded more than $10,000 for legal costs when she took her case to the ERA - on top of more than $6275 already awarded for lost wages and compensation.
However, an Oamaru meat worker sacked for squirting a colleague in the face with a high-pressure hot water hose failed to get his job back.
In the past two years, 811 of the authority's determinations ruled in favour of the employee and 691 in favour of the employer.
Employers and Manufacturers Association employment services manager David Lowe said despite the ratio of determinations favouring workers, he did not believe the authority was biased.
"I think that the employment law requirements that it is their job to interpret are difficult for employers to get right. We certainly know from the statistics that when it comes to performance-related matters, employers get that wrong 85 per cent of the time."
The authority had been working hard to improve consistency between authority members' determinations, he said.
"Previously, the Wellington authority was operating quite differently to the rest of the country ... the average awards were much higher than anywhere else."
The average cost to an employer when they lost a grievance was $35,000, which was "almost crippling for some small businesses", he said.
Last year, the ERA received 1985 hearing applications, however only 914 cases made it through the full hearing process. Most were settled by mediation.
Cases are heard in Auckland, Wellington and Christchurch and determinations are legally binding. APNZ
By the numbers
Six Wairarapa ERA applications received in 2012, one determination
Eight Wairarapa ERA applications received in 2011, no determination
1985 total ERA applications received nationwide in 2012, 914 determinations
397 found in favour of employee, 311 in favour of employer
2239 total ERA applications received nationwide in 2011, 958 determinations
414 found in favour of employee, 380 in favour of employer