Australia is PNG's biggest trading partner. It's our largest recipient of aid and unwanted asylum seekers. To get there, we can catch any of the four or more daily flights that link the two countries. Or at low tide, we can simply walk across the border.

But come Saturday, getting there will be a whole lot harder. That's when PNG will invoke its ban on providing Australians with visas on arrival. In other words, Australian travelers of all types – tourists, business people, and yes, even think tankers – will need to obtain their PNG visas before they leave Australia.

And that won't be a simple, efficient, online process. It will require lodging applications at the nearest PNG consulate or overseas mission (or, ironically, an Australian mission if there is no PNG Government representation) and waiting for them to be processed, which in this author's experience, isn't fast.

This decision will make PNG the only Pacific Island country where Australians need a physical pre-departure visa. And the reason? Pure retaliation.

If you don't believe me, read the public notice posted by the PNG Immigration and Citizenship Service Authority on its website. It states clearly that the decision to ban Australians from the PNG Visa on Arrival Facility was made by the National Executive Council in December. But the PNG Government held off invoking the ban to give Australia an opportunity to re-consider its refusal to reciprocate the visa-on-arrival facility for Papua New Guineans traveling to Australia. When Australia didn't budge, the PNG Government decided to enforce the ban.

To misquote Oliver Hardy, this is another bilateral mess we're in and at the worst possible time.

As both countries are pre-occupied with the tragedy that is the Manus Island asylum seeker centre and all it implies, this on-arrival visa ban by PNG is a distraction that does not serve either country well.

Clearly the PNG Government is frustrated with Australia's long-standing refusal to loosen its visa requirements for Papua New Guineans traveling to Australia. PNG no doubt feels there should be some recognition of the depth of the relationship through easier entry requirements. It seems Australia's immigration authorities don't agree. It is sticking with the status quo which requires Papua New Guineans to apply either online or at a commercially-run visa application centre.

So PNG has decided to retaliate. But unfortunately for PNG, it’s a retaliation that will largely harm its own interests.

At any one time, according to DFAT, there are over 10,000 Australians in PNG and a similar number of Papua New Guineans in Australia. While it's not one of Australia's favourite tourism destinations, PNG is a very important destination for business travelers. And it's in this area that the ban will be felt most. In 2012, Australia was the market for 40% of PNG exports. Japan, the second highest, took just 11.7%. There are similar figures on the import side, with PNG sourcing 34.4% of its imports from Australia, followed by Singapore at 14.3%. This vital trade relationship is kept vibrant and healthy by a steady flow of Australian business visitors to PNG.

This decision is also at odds with what appear to be shared bilateral aspirations to enhance people-to-people links. These aspirations were set out by Australian Foreign Minister Julie Bishop during her recent visit to PNG, when on several occasions and in media releases she referred to strengthening ties, including through the establishment of the PNG-Australia Network . That network, to be hosted by the Lowy Institute, is aimed at encouraging stronger relationships between the two countries' businesses, entrepreneurs and students. But to do that effectively, those people will need to be able to move smoothly between the two countries.

Clearly the PNG Government has the right to decide how to monitor the flow of visitors to its country, just as Australia does. But the direction PNG is taking in returning to a dauntingly time-consuming process will be yet another irritant in this relationship, one which seems to be a magnet for irritants and worse.

Photo courtesy of Wikipedia.