Mayor Michael Bloomberg described it as a perennial dance between the city and the union representing the nearly 8,000 school bus drivers, but this latest possibility of a strike as soon as January 2nd is being taken seriously by city officials.

The sticking point: the city put out bids today on some of the school bus routes, for the 2013-2014 school year, but the union wants its members’ jobs to be guaranteed. City officials say the law prevents them from offering any sort of job guarantees.

If the union goes ahead with the strike, Mayor Bloomberg says it could force more than 150,000 students across the city to find an alternative way to school after the holiday break.

“In a year when our school kids have already missed a week or more of school because of Hurricane Sandy, striking against our school children we think would be totally irresponsible,” the mayor said.

Union officials with bus drivers’ Local 1181 of the Amalgamated Transit Union did not respond to a request for comment.

Bloomberg and Schools Chancellor Dennis Walcott said students impacted by the strike who live near public transit would be eligible for free Metrocards. For students who cannot access mass transit the city says it will reimburse parents who drive 55 cents per mile, or the full cost of a taxi or car service ride.