There is strong support for the Trans Pacific Partnership (TPP) on the East Coast, despite a protest attack on a Whakatane electorate office, Anne Tolley says.
The Social Development Minister's office was firebombed overnight and painted with graffiti opposing the TPP.
It was one of a number of attacks related to TPP protests, with some senior MPs advised to close their electorate offices.
Mrs Tolley told Checkpoint with John Campbell a couple of molotov cocktails were thrown through the window, but did not catch light as they landed on a tile floor.
Anti-TPP graffiti was also painted on the walls.
Despite the protest, Mrs Tolley said her electorate would benefit hugely from the TPP, as they were primary producers for a range of things, including wine, beef, kiwifruit and dairy.
"Over the last couple of years, you know, quite a number of people have talked to me about their concerns with the TPPA.
"And so the opportunity to talk through some of those issues doesn't always satisfy people's fears, but by and large I've had good support across my electorate for the signing of the TPPA."
The head of security for Parliamentary Service said a number of electorate offices had been vandalised over the past few weeks.
The security official, who spoke on condition he would not be named, said they had given a "range of advice" to MPs including posting more security staff and even shutting some offices down.
"It's a range of different things, some offices we've simply said follow your normal security practices. Others, we may recommend that they close the office temporarily", he said.
But he added it was the MP's call whether to shut the office down.
The electorate office of the Auckland Central MP and Civil Defence Minister, Nikki Kaye, was shut yesterday and extra security put in place.
Ms Kaye said her staff were pretty worried when their electorate office was spray-painted last week.
On Monday, Gerry Brownlee's office in Christchurch was vandalised, but it was not clear whether there was any TPP protest involved in that incident.
Parliamentary service oversees 128 offices.
Police are still gathering evidence on the attack on Mrs Tolley's office.
In a statement, Prime Minister John Key, described the attacks as "hugely disappointing" and said MPs and staff worked incredibly hard
"People always have the right to peaceful protest and are free to do so, as long as they don't break the law or put anyone in harm's way," he said.
Mrs Tolley and her staff gathered at the office on The Strand after being notified of the vandalism about 6.30am. Police were also at the scene collecting evidence.
A protest against the TPP in Whakatane yesterday was peaceful, she said. The trade deal was signed by ministers of 12 countries at SkyCity in Auckland yesterday, amid demonstrations by thousands of people.
"We were aware there was a protest march in town yesterday, and that went perfectly well and it was very peaceful. It was no trouble and that's what democracy is all about. People are perfectly entitled to protest but this sort of action is unacceptable."
It followed the act of vandalism on Mr Brownlee's Christchurch office on Monday. Police said CCTV footage showed two men breaking a window and pouring accelerant into a ground floor room of Mr Brownlee's office.