New Jersey Gov. Chris Christie, who pulled the plug last month on a new commuter-rail tunnel beneath the Hudson because of its high cost, said yesterday he would consider contributing to a cheaper alternative: extending New York’s No. 7 subway line to Secaucus.

Christie said the subway plan not only would cost less than the scrapped tunnel, it would connect to Penn Station and Grand Central and would receive funding from New York City and state.

The subway extension would make use of parts of the commuter-rail tunnel already built.