"The range of subjects will be further expanded in 2020 and beyond," she said.
However, Glendowie College principal Richard Dykes, who chairs the Auckland Secondary School Principals Association, said glitches in the early online trials showed that the authority was right to move slowly.
"It's a very difficult area because you are dealing with technical issues. Anyone who has used a computer will know the likely problems you have with that," he said.
"So I think it's really important that they take time to get it right, because you are dealing with a very high-stakes qualification.
"Will they get to do it in 2020, and are they going to get all schools online by 2020? At least they are moving in the right direction."
"Laptop malfunctions" were blamed for glitches in early online trials in 2016.
Last year a number of students sitting Level 2 Media Studies online were presented with multiple log-ins to different subjects, and were unable to open the Media Studies assessment.
In February, NZQA said 258 students at 38 schools were incorrectly given zero marks in the online exams last year.
Documents released in March included feedback from one school saying, "We were run off our feet solving problems over the whole exam. It had us thinking about pulling out altogether."
Later feedback from participating schools outlined other issues including a slow computer that meant words took about 30 seconds to appear, frozen screens, lost internet connection, and copy-and-paste issues.
In August, students at Botany Downs Secondary College started a petition against having to sit an exam online because it would force some of them to buy new laptops.
But Kilkelly said an evaluation found that "nearly all survey responses from students, who have taken part in a digital exam, preferred an online exam rather than written exams".
Since 2014, almost three quarters of all secondary schools and around 30,000 students have experienced at least one digital trial or pilot exam.
This year's exams begin next Wednesday, November 7, and end on November 30.
Students can find helpful information to assist their exam preparation at NZQA's student hub webpage or by following NZQAofficial on Facebook and Twitter.
NCEA numbers
Last year
Total students: 146,000
Students who sat online: 5130
This year
Total students: 140,000
Students sitting online: 8000
Source: NZQA