LuaLua, 26, has travelled to Greece to discuss a £2.8million move to Olympiakos after three years at Fratton Park.
Redknapp admits LuaLua is keen to head abroad for a new challenge and is predicting the DR Congo forward to be a hit.
"Lua is a great player, but he wants to move on," Redknapp told The News. "He wants a change.
"He wants to play in a role behind the strikers and he wants to move abroad.
"I've no doubt he'll go away and be a great player for Olympiakos.
"He will get to play in the Champions League there for them. He's been a top Premier League player and he'll be a top player for them."
Pompey are set to replace Lua Lua with the signing of Argentina international Jonas Gutierrez from Mallorca.
Chief executive Peter Storrie is due to finalise the transfer next week and played down concerns about the winger's former club Velez Sarsfield still owning the player.
"That's not a problem," said Storrie. "We would buy the player 100 per cent from Mallorca and they would have to deal with the Argentinian club.
"It's not like the situation with third-party ownership we are seeing.
"He is a very good player. We don't want to lose out on him, so hopefully we can put it to bed."