Canada's airline regulator has ordered regional carrier Porter Airlines to rewrite its policies on lost baggage and delayed flights to make clear passengers may be entitled to compensation.

The Canadian Transportation Agency (CTA) ruled that Porter's current policies were "silent" and "unreasonable" because they do not state that the airline can be held liable if a flight is late, rescheduled or a passenger's baggage is misplaced, which is required by law.

The 32-page decision, which was released Wednesday, said the airline must make the amendments within 20 days.

Spokesman Brad Cicero says Porter was already in the process of making the changes when the complaint was filed, noting that its compensation policies have been in place for years — even if it wasn't stated clearly.

"We have already been, for years, offering compensation in these types of circumstances," Cicero said Thursday.

"We do have things like meals and travel vouchers available if you have a delayed or cancelled flight. (The ruling) doesn't necessarily change what we already have in practice."

The complaint that sparked the agency's review was filed in April 2012 by Gabor Lukacs, an airline passenger rights activist.

"This is a significant gain for passengers, because the tariff (policy) is the blueprint of how the airline is supposed to behave and treat passengers," he said in an email from Halifax.

The former mathematics professor at the University of Manitoba, said passengers may know that they may be entitled to meals, hotel and ground transportation from an airline if there are issues with their flights, but some may not know they can also seek other forms of compensation.

He said passengers were left confused by Porter's policies, because they did not explicitly state their liability in these types of situations.

Lukacs said passengers may also be reimbursed for lost income, and inconvenience, which he admits may be more difficult to get.

"The bottom line is: passengers should always assert their rights and fight for what they are entitled to," he said.

Last year, Lukacs was also successful in similar complaints again Air Canada and WestJet.

In the first case, the transportation agency ordered Air Canada to replace its international baggage liability rules.

The policy had stated that the airline wasn't responsible for valuables such as money and jewelry in passengers' checked baggage on certain itineraries.

In the second case against WestJet, the agency ruled that the airline's $250 limit for luggage compensation was too low and ordered it raised to $1,800, the amount dictated by the relevant international regulation.

An attempt by the airline to have the agency's ruling rejected was recently dismissed by the Federal Court of Appeal.

Porter flies to about a dozen cities in Eastern Canada and the United States and carried 2.45 million passengers last year.