Kalyn Ponga's long-term NRL future looks to be at five-eighth after Newcastle confirmed the signing of Cronulla's Lachlan Miller on a three-year deal.

Miller will join the Knights with immediate effect, paving the way for Ponga to make a heavily touted switch to the halves.

Ponga has dabbled in the No. 6 role in the past but now appears set to make a permanent move to the halves at the start of the season.

Miller, a former rugby sevens player, switched codes to join Cronulla last season after featuring in the Tokyo Olympics.

"We have signed Lachlan predominantly to play fullback, we also believe he has the versatility to play multiple positions," said Knights football boss Peter Parr.

"He is a gifted athlete, with great speed and a player who will add excellent value to our squad."

Elsewhere, Parramatta have announced the retention of centre William Penisini until the end of 2025.

The 20-year-old was part of the Eels squad that reached last year's grand final and also won representative honours for Tonga.