Toronto Zoo will reopen on 15 June, five weeks on from a strike which closed the attraction in a dispute over job security.

More than 400 members of staff including zookeepers, horticulturists, trades people, maintenance, administration, concession and ride operators at the zoo commenced strike action against their employer, after negotiations over secure contracts had broken down.

Initially, the zoo said that only full-time permanent members of staff with 11 or more years of service would have protection from losing their jobs to independent contractors. The Union wanted protection after four years. The stalemate was finally broken, after workers agreed protection after eight years. Board members also voted 5-3 in favour of a new four-year contract for unionised staff.

“While we are looking forward to returning to work and to looking after the animals we so deeply care about, our employer should be under no illusions that this was an easy decision for us to collectively take,” said Christine McKenzie, president of the Canadian Union of Public Employees (CUPE) 1600.

“This was a month of struggle, for the right reasons, and I am incredibly proud of what our members have achieved.”

The city-owned attraction, which is Canada’s largest zoo, said it would reopen on Thursday (15 June), with staff returning to work today (13 June) in preparation for the reopening.

“Following the ratification process, Toronto Zoo is pleased to announce it will be re-opening to the public on Thursday at 9 am,” said a statement from the zoo.

“Unionised staff will be returning to work on Tuesday and exempt staff will return to their regular duties at the same time.

“We want to thank our valued guests, members and clients for their patience during the labour disruption and we look forward to their continued support for the Toronto Zoo as a world leader in conservation, education and scientific programmes.”

The strike also resulted in the postponement of the scheduled public launch of the Wildlife Health Centre – an CA$18m (US$13.6m, €12.1m, £10.7m) high-tech zoo hospital and laboratory with an atrium for public viewing – which was set to open next week.