"New Zealanders from across the country are standing together to support workers being unfairly treated," he said in his view via a media statement.
"This money will help feed the families of the people who have been locked out. It will keep the heaters on, and the bills paid."
Wagstaff said unions had been "incredibly generous" in their contributions.
"The level of support shows what can happen when we work together. It's been marvellous."
Pulp and Paper Union Kawerau secretary Tane Phillips said union members were in facilitation with Essity negotiators last week.
Phillips said last week it was "a bit early to tell" how the negotiations were going. "We're trying our best to make headway ... to get to an agreement."
145 workers have been locked out of their workplace since August 9.
Essity has said its previous offer equated to 14.7 per cent over three years, saying this was comprised of a 3 per cent increase each year.
There was also a one-off cash payment in the first year, making that year's payment equivalent to 8.3 per cent.
Peter Hockley, the general manager at Essity's Kawerau site, said in an earlier statement the company had no option but to initiate a lockout to try to secure an agreement, after 19 days of strike action, and continued wage claims that threatened the future of the site and jobs.
He believed the company had "well-remunerated" employees, who were among the "highest paid working in manufacturing in New Zealand, earning nearly double the median weekly earnings of New Zealanders".
