The 30-year-old has not made a big dent on the demanding links course in the past, but gave himself a boost with his tie for second at The Grange in Auckland at last year's Open.
"I went close last year and I know I can compete with these guys," he said.
Alker missed taking a spot on the US PGA Tour this year by two shots at the qualifying school.
He will travel the secondary Buy. Com Tour this year after several years on the Canadian Tour, where he won the Order of Merit in 2000.
His girlfriend, Tanya Wiffen, is carrying his bag this week, and even though he has had a layoff, it didn't show in the first two days.
"After the Christmas break, I'm a bit rusty, but I'm certainly getting there."
As for his closest rivals, Alker said there was no point looking over his shoulder today.
"I can't control what the other guys are doing. I've got to keep doing what I have been doing."
If he does that, with the fairways and greens hardening, he could yet make it six successive New Zealand champions of the Open tomorrow night.
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Full coverage: NZ Golf Open 2002
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Off the course: news related to the NZ Open