Workers at the Toronto Zoo could find themselves locked out at midnight, less than a week before the beginning of the zoo’s busiest period of the year.

Zoo management is meeting with union representatives today to try and negotiate a new agreement for more than 400 permanent, part-time and seasonal workers. The workers, represented by CUPE local 1600, include zookeepers, educational staff, veterinary technicians, retail workers and others.

On April 4, zoo management informed union negotiators that they intended to seek a “no board” report from the Ministry of Labour, which would enable either party to trigger a work stoppage.

Following the move, union officials said management had refused to negotiate in good faith and warned they are endangering the upcoming spring season.

“The zoo appears to be putting the entire spring season at risk, including the upcoming panda display by putting us on a fast track to a lockout,” said Christine McKenzie, president of CUPE Local 1600, in a press release issued April 8.

The union also called its demands modest and said it is not looking to strike.

For its part, the zoo has said it asked for a no board report when it appeared negotiations had hit an impasse. However zoo officials said they’re hopeful a resolution can be reached.

“We continue to meet today and we're hopeful an agreement will be reached,” zoo spokesperson Jennifer Tracey told CP24 Thursday.

The zoo’s website says expanded hours are set to begin May 1 and continue on until September 7.

The zoo has been bracing for heightened attendance this year following the arrival of two giant pandas on loan from China. The deal to host the two pandas – named Er Shun and Da Mao – was sealed by Prime Minister Stephen Harper on a trip to China last year.

Neither side in the labour dispute has said exactly what the sticking points are in negotiations.

More updates are expected later in the day.