Manyama has notched up 10 goals and five assists for the Citizens in all competitions this season, while Ngoma has struck thrice and provided 10 assists.
Ajax will host their derby rivals at Cape Town Stadium tonight (20h15).
Lebusa told his club's website: "Their attack is very, very dangerous – I think it is one of the best in the PSL. We just have stay focused, remain firm and defend well against them because we saw that they are very good on the counter, so we have to counter control their swift attacks on goal."
The Urban Warriors lost the reverse fixture 1-0, with Lebusa determined to help his side claim bragging rights on this occasion.
"It is a big one, a Cape derby and obviously we want to win – they want to win – we are playing for pride so I think it will be a tough game."
Meanwhile, the 24-year-old expressed pride at recently notching up a 100 appearances for Ajax, having made his PSL debut five years ago with the coastal outfit.
"It is a very nice feeling to have passed 100 games for this club, for the club I made my professional debut with. I am really happy, it is really exciting and I feel honoured."