Matty James' third goal of the season looked to have secured only Leicester's second win in 12, a rotten run which has seen them slump from second to seventh.
But LuaLua, on as an early substitute for the injured Will Buckley, rescued Brighton when he cancelled out James' strike with just two minutes remaining.
Despite their poor run, Leicester did not start like a side lacking in confidence with Andy King heading wide and Michael Keane volleying over the top.
King then fired wide from inside the area before David Nugent's long-range effort was held by Seagulls keeper Tomasz Kuszczak.
But Brighton almost went ahead with their first real chance on the half hour, Inigo Calderon denied by a goalline clearance from Danny Drinkwater before David Lopez's follow-up was palmed over by Kasper Schmeichel.
Moments later Leonardo Ulloa met a corner from Andrea Orlandi, but the Argentinian striker could not keep his header down.
Leicester went close in the 35th minute when Jeff Schlupp played in King, whose rising drive was tipped over by Kuszczak.
Schlupp then found himself one-on-one with Kuszczak but his shot hit the advancing keeper's heel and Gordon Greer was on hand to complete the clearance.
Schlupp was still making a nuisance of himself at the start of the second half, driving one effort wide before shooting straight at Kuszczak.
Former Manchester United keeper Kuszczak then made a fine save to deny King, Ben Marshall fired over from 20 yards and Keane headed James' corner wide.
Brighton almost took the lead in the 71st minute when LuaLua crossed into the area, but Ulloa poked his shot wide.
And the hosts were made to pay two minutes later when they failed to deal with Paul Konchesky's long throw and the ball fell to James, who cleverly switched feet before smashing it into the net.
They could have had a second, but Liam Bridcutt bravely blocked a fierce strike from Chris Wood.
But instead LuaLua grabbed what could prove a vital equaliser when he collected a pass from Dean Hammond, cut in off the left wing and rifled his shot inside the near post.