Combine chicken stock, oyster sauce, soy sauce and sugar in a small bowl, and set aside.
In a large frypan, heat the oil over medium-high heat. Add curry powder, garlic and ginger; stir-fry for 10 seconds. Add capsicum, onions and spring onions; stir-fry for 3 to 5 minutes. Stir in chicken stock mixture and bring to a boil over high heat. Add prawns and peas and cook until hot. Add noodles and cook until dish is heated thoroughly. Serve immediately.