International passenger traffic on Australia's airports saw a sluggish growth in April as fresh government figures showed that a total of 2.059 travellers passed through in and out of the country in the month, which is a 4.2 percent improvement from the 1.976 million posted on the same corresponding month last year.

The Department of Infrastructure, Transport, Regional Development and Local Government said on Thursday that the numbers marked the 13 consecutive months of increasing international passenger traffic though it noted that the new result was the slowest pace seen since August of last year and way below from the previous months.

The department report said that the slide marked "a return to moderate growth after the months of September 2009 to March 2010 recorded month on month increases of more than nine per cent."

It said that while airline seat capacity shot up by 6.2 percent in April, overall seat utilisation declined by 1.6 percentage points to 73.2 percent.

Qantas Airways Ltd appeared to have secured the largest international traffic market share with its 27.9 percent in April, though the numbers showed a decline from its 29.3 percent market dominance posted last year.

The figures represented both performances from Qantas' mainline services and its low-cost subsidiary, Jetstar while Singapore Airlines and Air New Zealand came next to the leading carrier with posted 9.1 percent and 8.6 percent of market shares respectively.

On the other hand, budget carriers captured a big chunk of market share from their full-service counterparts in April as AirAsiaX, Indonesia AirAsia, Jetstar, Pacific Blue, Polynesian Blue and Tiger Airways posted a combined 18.3 percent of all international traffic in the same month, coming from the 15.1 percent the low-cost airlines posted in the same month last year.

In a related development, Transport Minister Anthony Albanese said that liberalisation of the international aviation market should be fair and balance, telling a conference of the International Aviation Club in Washington DC that "opening up third and fourth freedom capacity, while retaining outdated ownership restrictions, and prohibitions on fifth freedom services, does not deliver a balanced playing field."

Mr Albanese said that in order to effectively compete in the global aviation industry, his country's fleet of airlines "would require usable fifth freedom rights if they are to compete with the geographically advantaged carriers who operate from mid-hemisphere hubs in Asia and the Middle East."

The freedom of the air is the set of rights allowing airlines to fly and land in another country's airspace in which the third and fourth freedom provisions guide an airline on its flight from its home country en route to another destination nation.

The fifth freedom carries the airline's rights to service routes between two destinations out of its home country, which is also the destined point of start or end of the flight plan.