A spoof advertising campaign promoting an Australian invasion of New Zealand has prompted mirth and outrage on both sides of "the ditch", as the Tasman Sea separating the two countries is known.

The idea was dreamt up by the producers of an Australian television show, The Gruen Transfer, which focuses on the advertising world. In one segment, "The Pitch", ad agencies compete to fulfil an impossible brief.

Last week, they were asked to devise a campaign selling a military takeover by Australia of its closest neighbour and most bitter sporting rival. One came up with the slogan, "The New Zealand invasion. There's a day off in it for you".

A voiceover, accompanied by scenes of beer-swilling men, women in tight T-shirts and steaks grilling on a barbecue, bemoans the dearth of public holidays at this time of year. "So this Saturday we're going to war with New Zealand. It'll be over by lunchtime, and to celebrate, the whole country gets Monday off. And then, every year, we can crack a beer to mark the day we smashed the Kiwis."

Another agency came up with an advertisement based on a tourism campaign that markets the land of rugby and sheep as "100 per cent pure New Zealand". Against a backdrop of rolling green hills and pristine beaches, it states, "0 per cent Air Force, 0 per cent Navy, 0 per cent Infantry. 100 per cent there for the taking, 100 per cent too easy, 100 per cent ours". Fighter jets then roar over the idyllic scenery, and tanks move in.

Some observers wryly noted that a reverse invasion had already been mounted, with 500,000 New Zealanders living in Australia. Phil Goff, the New Zealand Defence Minister, told reporters: "We created a beachhead [on Bondi Beach] years ago, and they have yet to recapture it."

The New Zealand Herald invited readers to retaliate with suggestions of ways to promote a Kiwi invasion of Australia. One blogger suggested the slogan, "Our Country Sucks, Can We Come Live With You Guys?". Another proposed: "Australia. A country of well-balanced people, because they have a chip on both shoulders."