Emergency services are on alert in South Australia as much of the state faces a severe heatwave over the next week.

Police have asked the public to be vigilant to the dangers of bushfires, while known arsonists have been warned Operation Nomad patrols will be out in force.

Adelaide is facing temperatures above 40C for the next five days, as is most of the state including Renmark and Port Augusta.

The State Emergency Service (SES) has issued extreme heat warnings from Monday until Thursday.

Total fire bans have been issued for Monday in the Mid North, Mount Lofty Ranges, Yorke Peninsula and Lower South East districts.

The SES is urging people to drink plenty of fluids and keep in regular contact with elderly relatives, friends and neighbours.

It suggests people keep their homes cools by closing blinds and curtains.

Premier Jay Weatherill says people who do not have home air conditioning should consider heading to cooler public facilities such as cinemas, shopping centres and libraries.

The air-conditioned Adelaide Central Bus Station will be open for 24 hours to provide respite to those who may need it after hours.

This will continue until the extreme heat warning is rescinded.

Transport Department staff will also distribute bottled water to public transport commuters.

The RSPCA has warned just six minutes in a hot car can kill a dog.

“There is no reason to leave pets in vehicles in high temperatures or at any time,” said RSPCA South Australia executive manager of animal operations Kerriann Campbell.

READ MORE: What’s cranking up the heat this week?

As a result of the heat, Adelaide Metro will run fewer services during this afternoon’s peak “to ensure no loss of capacity”.

The services will run every 15 minutes instead of every seven.

Adelaide Metro said the move was standard practice across rail systems in Australia and changed timetables would apply from 3pm this afternoon.

“This plan helps us provide a more reliable service to customers allowing us to conserve train movements and be able to respond faster should there be heat-related issues,” Adelaide Metro said on its website.

“Providing fewer services in the afternoon peak will allow engineers to manage any heat-related infrastructure failures which may occur. All services will stop at all stations, and free bottled water will be made available at the Adelaide Railway Station.”

The following changes were announced:

• Belair line will run to a 30 minute frequency stopping at all stations, including Blackwood.

• Noarlunga line – will run to a 15 minute frequency stopping at all stations.

• Gawler line – will run to a 15 minute frequency stopping at all stations.

• Outer Harbor/Grange – will run to a 15 minute frequency stopping at all stations.

The changes are expected to remain in place until the weekend when the heatwave is forecast to end.

– with AAP