Mrs Brook, of Maori Hill, said new health and safety legislation would include a more ''severe'' penalty regime.
WorkSafe NZ had more resources for enforcing the safety obligations by prosecution, she said.
Consequently, employers needed to consider the safety of their staff on a snow day.
Mrs Brook said that as snow fell in Otago on Monday, many employers were considering safety, with NZ Post deciding to cancel all deliveries to Dunedin's hill suburbs.
Many workers in Otago needed to be ''out and about'' and under the new legislation it could be considered unreasonable for an employer to expect them to work in unsafe weather conditions, she said.
Some employers might need to provide safe transport to and from work because WorkSafe NZ and the courts could consider travel time to be covered by the legislation, she said.
If an employer contacted staff at home on a snow day and instructed them to travel to work, the employer could have created a ''safety obligation'' under the new legislation.
Another safety consideration for employers was if the weather was forecast to worsen, she said.
If staff got to work safely but the weather was forecast to ''close in'', it could hinder a safe passage home.
''The employer has to make a decision - do we let them go early, or do we insist they work out the full day.''
The legislation was designed to improve New Zealand's safety record and could change the decision-making process of employers.
''I think it will change behaviour, in that employers will think about safety a lot more.''
Wise employers would have a clear snow-day policy so staff knew their employer's expectations.
It could reveal the circumstances in which staff would get paid, or not, and the reasonable efforts they were expected to make to get to work, she said.
An employer could expect staff to have a backup arrangement for care of children, if school was cancelled.
Labour Minister Simon Bridges said he welcomed the health and safety regulations discussion document released last week, which outlined proposals for new health and safety regulations.
The regulations would help people to comply with the new regime when the new Health and Safety at Work Act came into force next year.
''Regulations remove the guesswork about what is needed to meet duties under the law,'' Mr Bridges said.
The document was part of reforms that aimed to reduce New Zealand's workplace injury and death toll by 25% by 2020.
Submissions on the discussion document close on July 18.
