Highlanders chief executive Roger Clark said the franchise had a good group of players signed through until 2019 and negotiations were continuing with other players.
Fekitoa and Naholo loom as the key players to sign before the end of the season while Liam Squire is another All Black who is understood to be have a deal which concludes at the end of this season.
Captain and fullback Ben Smith signed on to 2020 last week, halfback Aaron Smith is signed until 2019, as is loose forward Dixon, while first five-eighth Sopoaga is signed through until the end of next year.Clark said contracting was ongoing right throughout the year.
"You are always going through the contracting process. I would say there are five or six negotiations now that I would say are key players that we are trying to keep," he said.
"But they are all at different stages. All of them have the same agents so they can only do one contract at a time so we can’t do them all at once.
"Players are different. Some of them put them as a high priority while others just want to wait until the end of the season.
"Others see where they are in regards to the All Blacks or overseas.
"We like to have 22 to 24 contracted by May for the next season ... but at the moment we look really solid right through until 2019."
Fekitoa is a player who has speculation around his next move. He has been a consistent player for the Highlanders since he made his debut in 2014, when he made a swift rise into the All Blacks.
But he had something of a frustrating year last season and lost his starting spot in the All Blacks to Anton Lienert-Brown. He may be thinking of heading overseas or moving to another franchise.
Clark said the signing of Ben Smith through to 2020, which was announced last week, was a real boost for the Highlanders.
"From our perspective, as a club, and the owners put it as a very high priority, it was great that Ben has decided to stay with the club."
Clark said the Brisbane Tens had been a good experience for the side and, despite what many critics said, the crowds were good and players enjoyed the two-day event. Minus the All Blacks the side made it through to the quarterfinals before it lost to Hurricanes.
The New Zealand sides had signed a four year deal to play the tens tournament.Clark said Otago flanker Dillon Hunt had joined the team to replace Dan Pryor, who is recovering from a knee operation.