Place the sausages in a large frypan over medium heat and brown on all sides. Remove from frypan and slice.
Melt butter in the frypan. Stir in the yellow onion, red onion and garlic and cook 2 to 3 minutes. Mix in red capsicum and green capsicum. Season with basil and oregano. Stir in white wine. Continue to cook and stir until peppers and onions are tender.
Return sausage slices to frypan with the vegetables. Reduce heat to low, cover and simmer 15 minutes or until sausage is heated through.