"There's definitely a possibility [of running both at London] and we're looking at the calendar," Willis said. "It's just a matter of taking things week by week and trying to stay healthy running the high mileage required for the distance, but I'm looking at a couple of different options in May or June, to have a crack at that [qualifying] time. If that comes relatively easily, then I'll definitely have a crack at it in London. It's after the 1500 in London so it's not really impeding my main plans for the 1500.
"It will never take over [from the 1500]. It might be something I can add equally with the 1500. I will definitely have that in my repertoire for the rest of my career. It's an event I've had success at in the past and it's a whole other ball game racing the Africans in the 5000m but you have to put yourself in the race to have a chance because sometimes those races can be very tactical, which would lend itself to more of a 1500m athlete."
New Zealand have had Olympic success in the 5000m - Murray Halberg won gold in 1960 and Dick Quax claimed silver in 1976 - but Africans have won seven of the last eight gold medals. Willis would need to go under 13 minutes 20 seconds to meet the A qualifying standard to join fellow Kiwi Adrian Blincoe on the start line.
It's the 1500m, however, where Willis' main focus remains and he's optimistic of his chances of medalling again in London.
"I feel like I've put in the training a gold medallist would need to do, but that has to continue over the next couple of months. I'm just really thankful to be in a position where I can say I've had some of the best training of my life over the past six weeks. As that continues, the sky's the limit in terms of what can happen in London."
New Zealand will name their preliminary track and field squad for London on Sunday, the final day of the national championships.
Eight athletes have already qualified - Valerie Adams (shot put), Willis (1500m), Stuart Farquhar (javelin), Jacko Gill (shot put), Nikki Hamblin (1500m), Brent Newdick (decathlon), Kimberley Smith (marathon), Blincoe (5000m) - but Adams, Smith and Blincoe will bypass the national championships.
Hamblin needs to convince selectors she is over her troublesome Achilles injury, and Gill will compete only in the under-20 category as he gears up for July's junior world championships and a tilt at the world record for 18 and 19-year-olds with the 6kg shot.
Others like Liz Lamb (high jump), Andrea Miller (100m hurdles), Monique Williams (100m/200m) and Tom Walsh (shot put) will hope to reach Olympic qualifying standards, and have until July to convince the selectors.