The Government is firmly against pay discrimination based on gender, but has shied away from supporting a bill aimed at eliminating any pay gap between men and women who are doing the same job.

The issue of pay equity has come to the fore after comments by Alasdair Thompson, head of the northern Employers and Manufacturers Association, about women being less productive because they take more sick days because of period pains.

The Human Rights Commission has released the Pay Equality Bill to allow employees to ask employers if they are receiving equal pay.

Prime Minister John Key appeared open to the bill in an interview on TVNZ's Breakfast yesterday morning, but by the afternoon he not only said he did not support it, but existing laws already outlawed discrimination.

"We're aware [of the bill]. We'd need to take a look at that. We haven't done that."

The principle of the bill was already reflected in the Equal Pay Act and the Human Rights Act, he said.

"We also would have real concerns if it was divisive in the workplace or had unintended consequences. I wouldn't say we support the [bill], but we'll have a look at it."

Mr Key said there were "a lot of reasons" why men were paid more than women, and he hoped people were not being paid differently just because of their gender.

"I don't know if they are or they aren't. I don't have any data on that."

According to the Quarterly Employment Survey in March, men are paid on average $27.54 an hour, 14.4 per cent higher than the $24.07 an hour that women are paid.

Equal Employment Opportunities Commissioner Judy McGregor said yesterday there were no privacy issues in the bill, because employers would not have to disclose other workers' pay unless it was relevant to an equal pay inquiry.

Green MP Catherine Delahunty has a private member's bill which would force employers to provide information on request to employees about what others are paid for the same job.

Labour leader Phil Goff said he would like to see both bills introduced so Parliament could scrutinise them.

"I think it's obvious that people doing the same job should get the same pay rate. We've had legislation for more than 50 years in that respect in the public sector, and we still haven't achieved the reality of it.

"You can overcome privacy considerations, but without transparency, we'll never turn principle into reality."

PAY GAP
* Average hourly pay for women $24.07
* Average hourly pay for men $27.54
* Difference 14.4 per cent

Source: March 2011 Quarterly Employment Survey, Statistics NZ