The French port owners want to build a new berth and slipway, and deepen a channel to upgrade facilities.
Businesses have welcomed the economic benefit but Sussex Wildlife Trust object to the loss of shingle habitat, and residents have said they will lose their only remaining sandy beach.
Newhaven Port and Properties have not commented to the BBC.
Helen Macaulay, from the town's chamber of commerce, said Newhaven needed more businesses and more jobs, and local concerns about infrastructure were being dealt with by the port.
The plans include a nature reserve but Ian Hepburn, from Sussex Wildlife Trust, said the development would damage coastal shingle and species there including reptiles, invertebrates, breeding birds and plants.
Former town councillor Rod Main said West Beach had already been closed by the port and this expansion would see the town lose its one other remaining area of sandy beach.
Calling for West Beach to reopen, he added: "This company are just taking away every sandy beach we've got."
A report submitted to Lewes council said the plans would help to regenerate Newhaven and create jobs, and the expansion would provide overspill space for the new Rampion wind farm.
Officers said it was an opportunity to create a modern port, and the benefits outweighed harm such as the loss of sandy beach, impact on surf conditions, and effects on ecology and archaeology.
The plans will be considered later.

The former Wales fly-half's long-range drop-goal was the highlight of an otherwise low-key first half.
Bath's Harry Davies and David Denton had tries disallowed before Semesa Rokoduguni intercepted to score.
But Rhys Priestland crucially missed the conversion and Bristol held on to move two points behind Worcester.
Mark Tainton's side remain bottom of the table despite the victory, which ended their seven-game losing streak, while Bath are in the final play-off spot just a point above fifth-placed Leicester.
Veteran Henson won 33 caps for Wales between 2001 and 2011 and got the better of the kicking battle with his opposing number 10 and countryman Priestland.
Bath's Davies and Denton were denied scores by last-gasp tackles from Will Hurrell and Alby Mathewson respectively, on both occasions their feet ending up in touch.
The Premiership's record try-scorer Tom Varndell was forced off against his wishes after failing a head injury assessment but, in front of their biggest crowd of the season, they stood firm to defeat Bath for the first time since December 2006.
Todd Blackadder's side have now lost their last four away games in the league.
Bristol interim head coach Mark Tainton:
"Our defensive effort was massive and to beat our neighbours was fantastic as we stood up to them but the fight against relegation will go all the way to the end.
"Gavin will be sore after his comeback but he controlled the game as he was accurate with both his place kicking and line-kicking.
"He's a confidence player and grew into the game. He's a big man so he threatens the defence before releasing good off-loads and pop-up passes."
Bath director of rugby Todd Blackadder:
"We beat ourselves as we didn't hold on to the ball enough and had plenty of opportunities to win.
"The breakdown was messy where they did a good job at slowing us down, but there are no excuses as Bristol showed real tenacity and never stopped believing."
Bristol: Woodward; Lemi, Hurrell, Piutau, Varndell; Henson, Mathewson; Bevington, Jones, Perenise, Tuohy, Evans, Eadie, Lam, Crane.
Replacements: Crumpton, O'Connell, Ford-Robinson, Jeffries, Fenton-Wells, Williams, Pisi, Wallace.
Bath: Homer; Rokoduguni, Joseph, Tapuai, Davies; Priestland, Cook; Obano, Batty, Lahiff, Stooke, Ewels, Ellis, Denton, Grant.
Replacements: Van Vuuren, Marfo, Palma-Newport, Douglas, Mercer, Homer, Hastings, Clark.
Referee: Greg Garner.
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Expansion plans put forward by Newhaven Port have been recommended for approval by Lewes councillors.
[NEXT_CONCEPT]
Gavin Henson kicked all Bristol's points on his injury return as they beat rivals Bath for the first time in 11 years to boost their survival hopes.