Campbell said getting women into executive positions was harder than on a board, and said it was disappointing that about 40 companies on the NZX had no females on their board.
"If you as a leader on a board make the decision that you are not going to have a gender imbalance on a board that's all it takes."
"There are plenty of women who are fully qualified and eager to fill board positions. It is absolutely not hard to do, it just needs the will to do it," he said.
"There is no obstacle is what I would say. The obstacle is one that is only in the minds of the people who are making the board decisions. That's what has got to change."
PwC chairwoman Michele Embling said the more women were appointed to boards, the more others would look to this and start to make changes as well.
One of the more encouraging changes she had seen was the shift in language around gender diversity, from what was previously viewed as a moral decision, to what she said was now viewed as a smart business decision.
Global Women chief executive Miranda Burdon said the "avalanche" of evidence highlighting the benefits of a diverse board and executive team backed this.
As part of the NZX push to increase reporting around gender statistics, the organisation introduced new rules in 2016 requiring NZX-listed companies to have a gender diversity ruling with measurable objectives which they would report against annually.
According to Chorus chair Patrick Strange, shareholder activism was a growing trend.
He said it was likely in the coming years that major investment firms would require
companies to have strong policies in place on gender equity otherwise they may refuse to invest.
He said moves in the UK to "name and shame" companies with no women on their boards or executive teams could also work well.
Miranda Burdon said although gender equality in companies needed to improve, it was important to note that a few years ago the number of women on boards was about 12 per cent - a figure which has since risen to almost 18 per cent.
"In this day and age there is no reason why a board should not have a 50/50 gender split," she said.
"Given the evidence around the positive impacts of a diverse board, it's almost irresponsible in that role now to not ensure that."