Monster ratings for the season premiere of “The Walking Dead” have catapulted AMC’s ad rates into NFL territory, The Post has learned.

The fourth season debut of the zombies-versus-humans drama, which drew a best-in-class 16.1 million viewers, has allowed the cable network to ask for as much as $600,000 for a 30-second spot, Madison Avenue sources said.

That would be an astounding sum for broadcast — and is jaw-dropping for cable.

By comparison, Sunday-night NFL games, the usual top ratings draw, have ad rates around $570,000, according to Adweek.

AMC’s Sunday-night drama is the No. 1 among 18- to 49-year-olds this season — and

even outdrew NBC’s NFL coverage in the key advertiser demographic.

DVR playback is expected to grow the overall audience for the “Walking Dead” to 20 million.

“It’s unbelievable, spectacular,” Gary Carr, head of broadcast ad agency TargetCast, told The Post.

“It’s pretty frickin’ amazing that this ad-supported show, opposite football and Showtime’s ‘Homeland’ and HBO’s ‘Boardwalk Empire,’ can do these numbers.”

With the strong ratings in hand — the audience for “Walking Dead” was larger than that of all of its rival Sunday-night dramas combined — AMC, run by President Charlie Collier, is seeking as much as $600,000.

On Monday, Adweek named CBS’ “Big Bang Theory” the priciest non-sports show on TV at $326,000.

If ratings for AMC’s No. 1 drama hold, “Walking Dead” could sprint to the top spot.

CBS’ ad prices are based on the less expensive upfront rates bargained for ahead of time, while the pricey AMC rates are for the scatter (or spot) ad market.

Smart ad buyers could have had ad spots on the “Walking Dead” in May for $300,000 to $400,000, some buyers told The Post, although for that price you got one original show plus two re-runs.

At the same time, the ad-sales team at AMC sold the season heavily during the upfronts, buyers said, potentially limiting AMC’s upside.

Not that they won’t be able to score on the high ratings.

Korean auto manufacturer Hyundai is a big sponsor of the show. Movie studios hoping to grab high concentrations of young men also bought the series.

Chris Geraci, president of national broadcast at one of the biggest TV ad-buying agencies, OMD, said, “It is one of the highest-rated shows in cable, it’s a very well-distributed network, and the dollars will follow.

“This shows that people will pay attention regardless of the platform,” he said.

AMC Networks, run by CEO Josh Sapan, closed Tuesday at $69.19, up 3.4 percent, giving the media company a market cap of $5 billion, bigger than sibling MSG’s $4.4 billion.

AMC, which began life as a movie-rerun channel, has been transformed in recent years, fielding critically acclaimed hits such as “Mad Men” and “Breaking Bad.” The latter series recently ended its run with a finale that bagged 10.3 million viewers.