MT Newswires -ShutterstockHere are the NZX-listed companies with the biggest gains on Tuesday. Gentrack Group (NZE:GTK): +3%, NZ$3.80Scales Corporation (NZE:SCL): +3%, NZ$6.75Ventia Services Group (NZE:VNT): +3%, NZ$7.16Westpac Banking Corp (NZE:WBC): +3%, NZ$46.61Briscoe Group (NZE:BGP): +3%, NZ$4.79Vista Group International (NZE:VGL): +3%, NZ$2.58Santana Minerals (NZE:SMI): +3%, NZ$0.60CDL Investments New Zealand (NZE:CDI): +2%, NZ$0.66Oceania Healthcare (NZE:OCA): +2%, NZ$0.77Pacific Edge (NZE:PEB): +2%, NZ$0.27