Striking maintenance and emergency services workers have tabled a wage package that demands raises of 58 per cent over four years, the head of the St. John's International Airport Authority says.

"That's quite a substantial and unrealistic wage package," authority president and chief executive officer Keith Collins told CBC News Wednesday.

About 85 maintenance and emergency services workers represented by the Public Service Alliance's Union of Canadian Transportation Employees (UCTE) walked off the job Tuesday, claiming that marathon bargaining did nothing to turn around what the union calls concessionary demands from the authority.

But Collins said the authority has in fact been flexible, and that PSAC has refused to budge from the opening proposal it tabled in June.

"That's a proposal that we know is unrealistic, and so too do they, but they have not lowered that by a dime in the past [three] months," Collins said.

The striking workers handle a variety of duties, including equipment maintenance, fire services and runway clearing.

But an essential services agreement is in place, which will keep the airport running, with Collins adding that flight schedules should remain intact.

PSAC's Chris Bussey said the strikers are prepared to hold out.

"The biggest stumbling block without question is the concessions, but I tell you we are far apart on wages," he said.

"Our members haven't seen a wage increase since 2008, and as everyone knows the wages in Newfoundland have taken off."

PSAC, which had not disclosed its wage offer as the strike began, said it wanted to bring the striking workers to a pay level comparable with other large airports.

Collins said the airport authority has submitted a counterproposal worth 31 per cent over eight years.

"There's quite a gap there," he admitted. "We have indicated to the union that we have flexibility in all areas of the contract to keep on negotiating and moving."

Meanwhile, Collins challenged the union's claims that the authority plans to strip workers of benefits they enjoy.

"They are being characterized as clawbacks and concessions. They are simply business changes," he said.

As an example, he said the authority would like to change the no-layoff policy that it adopted a dozen years ago when the Government of Canada transferred ownership.

Collins said that all current employees would continue to enjoy that right, but new hires would not.

"When they talk about concessions, that's what they're talking about," he said.