Peter Dutton’s plan to impose increased security screening charges on regional airports has come under attack in the Senate and the Coalition party room.

Centre Alliance senator Rex Patrick has lodged a disallowance motion, citing departmental documents obtained under freedom of information that changes proposed by the home affairs minister could see fares from Whyalla increase by $54 to $70 per passenger.

In December Dutton made regulations consolidating seven categories of security controlled airports into four, with the result that at least four regional airports will now have to adopt the more stringent screening requirements of larger airports.

On Tuesday Liberal MP Rowan Ramsey and Nationals MP Barnaby Joyce, whose regional electorates of Grey in South Australia and New England in New South Wales will be worst affected, raised the issue in the Coalition party room.

The pair were supported by Nationals senator Matt Canavan, who said he had raised the issue with Dutton, noted it was still “unresolved” and labelled it a “barbecue stopper” in regional areas.

Canavan later told Guardian Australia people in country areas “should not have to bear a higher cost in responding to terrorism just because [they] live in a country area”, while Ramsey has labelled the impact of the changes uneven and unfair.

Dutton did not respond to his critics in the party room, but Scott Morrison said he expected to see further discussions on the topic.

Infrastructure department documents, seen by Guardian Australia, note that although the government set aside $50.1m to buy new screening equipment, the changes are expected “to create significant new and ongoing security operating costs” for Whyalla Airport.

Patrick has lodged a disallowance motion, which is due for a vote on 12 May, which could see Nationals senators cross the floor to help remove the new rules, if Labor is prepared to support it.

On Monday Ramsey told Guardian Australia he would raise the issue in the party room, because three affected airports – Port Lincoln, Olympic Dam and Whyalla – are all in his electorate. The fourth, Armidale, is in Joyce’s seat of New England.

“When this legislation was first proposed I warned it will unfairly and unevenly impact on small regional airports,” Ramsey said.

Ramsey proposed that smaller airports with fewer than 200,000 passenger movements a year “should receive come help with their security operating costs”.

“These are fragile services already which are only running on the goodwill of the airline operators,” he said.

“Extra costs will be passed on to operators, who will pass them on to people buying tickets … it will only hasten the demise of the services.

“I’m working very hard on this and still hopeful of getting a result.”

On Tuesday Canavan told Guardian Australia he wanted to ensure “regional travellers are not unduly impacted by the necessary changes to security”.

“The government has already provided assistance to regional airports to adjust,” he said.

“I am engaged in constructive discussions with minister Dutton’s office to assure myself that this assistance is sufficient.”

Patrick said regional flights are “the lifeblood of regional townships. The charges associated with the security screening … will raise costs, which in turn will stifle air travel and make some routes unviable,” he said.

“National security costs are exactly that: national. They should not be met by local councils, who in turn pass them on to passengers.”