"Some are saying it is a three-horse race for the title, but this is a four-horse race as far as I am concerned," he told the South Wales Evening Post.
"Neath are a good side and very much in the race. They have plenty of good players and are full time so we are anticipating a tough battle.
"This is a very important match for both clubs and we are really looking forward to it.
"We are top and want to remain there, but we know there will be ups and downs along the way.
"We are batting above ourselves at the moment as two of the teams below us, including Neath, are full-time and that makes a big difference in terms of preparation.
"But the lads are in confident mood at present and we are capable of getting another three points to set us up for the return at The Gnoll on New Year's Day," Lee added.
Kris Thomas is available again following suspension, but Lee Surman is banned so Legg has most selection options open to him.
Meanwhile, Neath's future is still shrouded in mystery due to their financial situation, with a winding up petition to be heard in London next month.
Although there have been calming assurances from club spokesman Chris Jones, there is unease clouding The Gnoll and it is how the players react to the uncertainty that could be key.
A feature of the match at Llanelli will be the battle between marksmen Rhys Griffiths and Lee Trundle, although the former Swansea man is currently in a barren spell of just two goals this season, while Griffiths has 19.