Attackers have ambushed a police convoy in the western Mexican state of Jalisco, killing 15 state police officers and wounding five as bullets riddled their vehicles in the deadliest single attack on Mexican police in recent memory.

The attack happened late on Monday as the convoy travelled on a rural road between the Pacific coast resort of Puerto Vallarta and Guadalajara, the state capital, the Jalisco state prosecutors' office said.

The death toll exceeded that of what had been the largest attack on law enforcement, an assault that killed 12 federal police officers in neighbouring Michoacan state in 2010.

Jalisco is home to a drug cartel known as Jalisco New Generation, which experts say is now among Mexico's most powerful. Prosecutors would not confirm the gang was involved in Monday night's attack, but it was hard to imagine any rival gang launching such a large attack on Jalisco's home turf.

While Alejandro Solorio, state security commissioner, did not say how the attack was carried out, he said the convoy was ambushed in a "cowardly attack".

Raul Benitez, a security expert at Mexico's National Autonomous University, said that "the serious thing about this attack was that it was very well planned and orchestrated, with a military-style strategy".

Local media reported that a vehicle was hijacked, parked across the two-lane road and set on fire to force the convoy to stop.

"This was planned. A lot of gunmen were involved. They blocked the highway to surround them [police] and attack with military superiority," said Benitez.

He said it was the first time a cartel appeared to be mounting a direct, head-on challenge to authorities. Gunmen from other cartels have been known to open fire on police and soldiers, but it is usually because they are being pursued and want to escape capture, he said.