In a large resealable plastic bag, combine the teriyaki sauce, oil, garlic and pepper. Place the tuna in the bag. Seal the bag with as little air in it as possible. Give the bag a good shake to coat the tuna fillets. Marinate for 30 minutes in the refrigerator.
Meanwhile, preheat the barbecue for high heat and lightly oil cooking grill hotplate.
Remove tuna from marinade, and place on barbecue. Cook for about 10 minutes or to desired doneness.
My 12yr old daughter made this for dinner last night, we used salmon fillets instead of tuna as that's all I could get in my rush. It was very tasty and I look forward to trying it again with the tuna. - 19 Oct 2010
This was absolutely the best tuna recipe that I have tried to date and I have been cooking for 32 years. It will definately go in our families favourites. D. Powell - 29 Sep 2008