A water main break in Chelsea closed six blocks of Seventh Avenue for hours Tuesday afternoon and caused some subway delays ahead of rush hour.

Police told drivers to avoid the stretch of Seventh Avenue between West 23rd and 34th streets and to steer clear of West 26th Street.

There were cracks in the asphalt between 25th and 26th streets with steam billowing from the holes in the asphalt. City workers were breaking up the road with a jackhammer as crews work to repair the break.

During rush hour, workers were still pumping water out of a hole in the avenue between 25th and 26th streets, a block cordoned off by police.

It was unclear as of 5:30 p.m. when the closed portion of the road would reopen.

Works lights had been rolled in, ready to go if the work stretched into the night.

The water main break occurred at around 3:45 p.m. Officials with the city Department of Environmental protection were called to the scene at West 26th Street along with the fire department, the FDNY said.

“I got here around 3-something and there was water all over the place. The traffic was outrageous. No one could get through,” said Carmen Paula, 74, of Williamsburg, who was bringing her mother to a doctor’s appointment on 26th Street. “That’s why we’re here so late.”

Straphangers were evacuated from the 1 subway line at 23rd Street just before 3:30 pm., a social media video shows.

Another video from the stations shows a stream of brown water running between the tracks.

Northbound 1 trains were running express until just before 4 p.m. due to water on the tracks. There were some delayed on the 1, 2 and 3 lines.