One Nation co-founder David Ettridge's bombshell $1.5 million legal action against Opposition Leader Tony Abbott is looming as unwanted distraction as the prime minister-in-waiting presses home his electoral advantage against the Gillard government.

Ettridge, alongside former Abbott staffer David Oldfield, was the other half of the "two Davids" that set up One Nation in 1997 as a vehicle for Pauline Hanson's dubious political ambitions.