Toyota customers waiting months for new cars are growing increasingly frustrated after a software upgrade left dealerships unable to track where vehicles are or when they will arrive.

Buyers of popular models, including the Toyota RAV4 hybrid and Toyota LandCruiser 300 Series, say dealers have been unable to provide delivery updates after the car giant rolled out a new computer system that temporarily disrupted vehicle tracking.

'Am I being spun a tall tale or is this real? Apparently a new software system was introduced in the last month or so. The dealer tells me they really have no idea when the car will arrive at the dealership,' a customer posted to a Toyota Facebook page.

Toyota Australia admitted the switch to the new operating system caused dealerships to temporarily lose visibility over incoming deliveries.

'Car is supposed to arrive May 31, but the dealer can't tell me where it's at due to software issues,' customer Keith Lord said.

Another customer, Steve Yucel, said he ordered a 2026 Toyota RAV4 Cruiser in December and was initially told it would arrive in March or April.

'Come mid to late April, the dealer informed me that the vehicle will be delivered on April 30, give or take a day or two,' he said.

'Two days before April 30, I was informed that the vehicle would not be delivered and they now have no idea when it will.'

Mr Yucel told news.com.au that dealership staff told him Toyota had started a software upgrade and had 'lost visibility' over where vehicles were in the supply chain.

'Your car is still at the port due to some complications with Toyota changing operating systems as in the software,' a dealership employee wrote to him on April 30.

The employee then told him Toyota had 2,000 cars backed up and was only able to release 300 cars a day.

The employee said in another text: 'Thousands of dealers are affected, and everyone is figuring out how it all works.'

In a Toyota LandCruiser 300 Series Australia Facebook group, many customers vented their frustrations.

'I was told mine would be here by now. Then also told there have been delays. They don't know where it is though. Now I have been told about a week away, but I don't think they know,' one person said.

'Unfortunately it's a Toyota-wide thing, and the transport and logistics side has had a few bugs,' another said.

In a statement, Toyota Australia denied claims vehicles were stranded at ports, but did say operational disruptions had occurred during the changeover to the new system.

'Some services and business operations may be impacted,' a Toyota spokesperson said.

'Vehicles continue to be supplied with minimal disruption, although we are aware that dealers have experienced reduced visibility regarding incoming vehicle arrival timings.'

Toyota denied customer delivery timeframes had been 'significantly impacted'.

'Vehicles continue to be processed with minimal disruption,' the spokesperson said.

'Vehicle flow has not been significantly impacted, though some dealers are experiencing reduced visibility of vehicle arrivals.'

Daily Mail Australia contacted Toyota for further comment.