Apple will fork over between $100 million and $150 million in advanced payments to the four major music labels in order to get its iCloud off the ground, three separate sources told The Post.

The Cupertino, Calif., tech giant has agreed to pay the labels between $25 million to $50 million each, as an incentive to get on board, depending on how many tracks consumers are storing.

The size of the advance payments have been a major hold-up for Google, which had been negotiating with the music companies and now will likely have to pony up higher fees to get a rival cloud service into action, said music industry sources.

A Google cloud service could now be in the offing as soon as September, said sources familiar with the talks. Steve Jobs is expected to unveil Apple’s iCloud service, a Web storage offering that frees space on hard drives and makes music available to Apple’s many devices, on Monday at its developer conference.

One executive explained that the cloud service will initially be free to people who bought their music from Apple’s iTunes store, but Apple is said to be considering a $25 a year charge in the future.

The music companies will divide the fee with Apple, with the tech firm taking a 30 percent cut, 12 percent going to music publishers, and the rest to the labels to divide with their artists.

Apple yesterday finalized its cloud deals with all labels and their publishing units, according to sources.