"Furthermore, you are instructed not to contact any of my clients... I also put you on notice that all/any Unite Union organisers/management will be formally trespassed and the police advised if you attempt to enter the private property of Darien Rush Security
at any time as you are not welcome.''
It is illegal for an employer to discriminate against workers because they joined a union, and unions are legally allowed to enter a workplace to represent members.
"Darien Rush shouldn't be part of the World Cup at all,'' Mr Minto said.
Almost 30 employees had been in touch with the union about concerns - with eight of them signing up - and the picket was hoped to bring "a flood of people to us'', Mr Minto said.
The tournament ran a "real risk'' of a strike if it stuck with Darien Rush Security, he said.
"We're not making a big issue of this at the moment... but [for] the last three weeks of the Rugby World Cup, staff are able to go on strike, and no one wants that situation.''
Under the Employment Relations Act 2000, strikes and lockouts are lawful after 40 days of bargaining.
After the All Blacks test at Eden Park earlier this month, a security guard wrote on his
Facebook page that it had been "hard work'' controlling the crowd because it was his first time doing security.
He was outside for eight hours without a break, and it was "scary'' as people got wild and tried to climb over barriers, the man wrote.
Darien Rush Security was responsible for crowd control at last November's Four Nations rugby league match attended by 44,500 fans, in which bottles and missiles were thrown at players and spectators.
The firm said through a public relations firm that it would not comment, but the company is understood to have retracted Mr Rush's email and requested good faith negotiations -without disparaging comments being made through the media - and the names of the employees who had approached the union.
Auckland rich-lister Trevor Farmer is one of the shareholders of Darien Rush Security, through his companies Hornbeam Holdings and Ironwood Trustee.
Darien Rush Security has recently lost contracts, including for the Britomart precinct.
Facilities manager Mark Sinclair said Darien Rush Security's service performance had "just dropped a little bit''.
However, other companies that have moved away from Darien Rush Security -including Kiwi Income Property Trust and Tasman Liquor - are understood to have changed operators for reasons other than performance concerns.
A Rugby World Cup spokesman said: "We are confident in the ability of DRS to provide the level of security we require for RWC 2011 matches.''
Liquidators told the Herald last month they were preparing court action against Darien Rush Security over a disputed purchase of Strategic Security, the security company that had held the Eden Park contract and was liquidated with $2 million in debt.
The police financial crime unit is currently assessing whether to pursue an inquiry into the company.
