The entrepreneur helping to bankroll Nick Xenophon's fledgling political party is launching a television ad campaign lambasting the Coalition for handing a $35 million contract to supply spectacles to Defence Force personnel to a multinational company based in a northern hemisphere tax haven.

The ads, which urge voters to "Please, please don't vote Liberal", have been funded and authorised by Ian Melrose, who has given $175,000 to the Nick Xenophon Team since its December 2014 launch.

The ads focus on the $33 million Defence contract currently held by Specsavers.