An internal email sent from National's chief press secretary to MPs, advising them about how to talk to media about bullying, has been leaked to the Herald.
The sender claimed to be a National MP, however the anonymous email did not come from a parliamentary email address.
The email provided talking points on how MPs should respond when asked by media about bullying.
It comes just days after National's internal polls – numbers the party keeps close to its chest – were leaked to media.
"Given the focus on bullying in the media lately and the launch of the Speaker's inquiry, please see some lines below in case stopped on your way in in the morning, if useful," the leaked email said.
"Parliament's a robust environment and it's demanding. We're working very hard for New Zealanders and the demands on the time of MPs and staff is extensive but we have a strong culture and people like coming to work because they know they're making a difference.
"At the same time, we need to make sure we have an environment where staff feel able to come forward with any concerns and that those concerns are dealt with appropriately.
"We sought assurances about that recently and we will take any feedback on board as a result of the inquiry under way at Parliament."
In a subheading, the email laid out what MPs should say when asked by media if National had a cultural issue.
"No we don't," it said.
"We work very hard for New Zealanders – MPs and staff - and we have a very strong culture. It's a good place to work.
"When issues come up we deal with them."
A spokesman for National said the party "regularly sends communications out widely to assist MPs and staff with their media and communications".
"It is up to those MPs and staff whether they choose to use it."
Speaking to media this morning, National Leader Simon Bridges appeared to be heeding the email's advice.
He referenced the party's culture several times.
"I know from my inquiries, from talking with Parliamentary Service and going around talking with staff that people want to come and work for us and they have a dedication to it – we have the right culture," he told media this morning.
Asked if an email had been sent around to caucus last night telling MPs to refer to the party's "strong culture", Bridges said he didn't know.
"The reality is I get a lot of emails – hundreds a day."
The leaked email comes just days after the Weekend Herald revealed MP Maggie Barry has been twice investigated over bullying claims this year.
It was revealed two employees in Barry's four-person office have accused her of bullying since May – one in a personal grievance complaint, and the other during the investigation of that complaint.
The leaked email also comes after National's internal polls had also been leaked to media.
Bridges this morning, however, did not want to talk about this, calling it "rumour and speculation".