From July 1, 2020, an on-the-spot fine of $1000 and four demerit points will apply to the offence of texting, emailing, using social media, watching videos or accessing the internet while driving.
The current penalty for driver phone use in WA is a $400 fine and three demerit points.
Touching your mobile phone while stopped at traffic lights or holding the phone while taking a call is regarded as a lesser offence and will incur a penalty of $500 and three demerit points.
WA joins the ACT in drawing this distinction between the severity of different types of phone usage on the road.
The WA government is taking a tougher stance after 31 people, or 19 per cent of all road fatalities, were killed on the state's roads in 2019 as a result of driver inattention.
Road Safety Minister Michelle Roberts said that over the past five years, WA Police had caught 77,000 drivers using their phones.
"These increased penalties send a strong message to drivers who engage in deliberate risk taking behaviour," Roberts said in a statement.
"I want to make it clear to motorists, that using your mobile phone to text or read emails or FaceTime while you're driving is incredibly dangerous."
The WA crackdown follows similar penalties taking effect in Queensland on February 1 this year, with Queensland Police issuing $1000 fines to 218 drivers in less than a week.
Road Safety Council chairman Iain Cameron said the tougher penalties reflect the "cognitive load" created by mobile phone use while driving.
“Last year saw a 48 per cent increase in the number of people killed in inattention-related crashes on WA roads compared to the previous five-year average," Cameron said.
“There is no excuse for anyone to use a mobile phone while driving, unless that use is within the law to make or receive a call on a phone that is securely mounted in the car."
WA and Queensland have some of the toughest penalties for driver mobile phone use in the country.
The penalties in other states are as follows:
New South Wales: $344 and five demerit points, with penalties rising to $457 in school zones.
Queensland: $1000 and four demerit points. Repeat offenders will receive a $2000 fine and double demerit points if caught again within 12 months from the previous offence.
Victoria: $496 and four demerit points.
ACT: $480 and three demerit points for handheld phone use and a $589 fine and four demerit points for driver using mobile device for messaging, social networking, mobile application or accessing internet.
South Australia: $534 and three demerit points.
Western Australia: $400 and three demerit points.
Northern Territory: $500 and three demerit points.
Tasmania: $336 and three demerit points.