CANBERRA, AAP – Scott Morrison has marked three years as prime minister with a plea for coalition colleagues to stay unified to remain in government.

Mr Morrison will surpass Julia Gillard this week and become Australia’s 14th longest-serving leader.

He is the first person to serve three years as prime minister since Ms Gillard, with his tenure longer than Malcolm Turnbull, Tony Abbott and Kevin Rudd.

The 53-year-old addressed coalition MPs and senators during a joint partyroom meeting in Canberra on Tuesday.

“You remain in government when you remain together,” he said.

“You do your job, I do my job.”

Mr Morrison said the government knew how to get things done when working together.

“We’re going though some of the most difficult times this country has experienced in history, certainly since the Second World War,” he said.

“We continue to save lives and livelihoods.”

Labor MP Julian Hill let rip at Mr Morrison, saying the public had now had three years to get a true sense of the prime minister.

“His incompetence. His failure. His refusal to take responsibility. His blame shifting. His shape shifting. It’s always too little too late,” Mr Hill told reporters.

“This is a pattern we’ve now seen in these three long years. My God, it feels like longer.”

The opposition MP said Australia could not afford three more years of Mr Morrison’s leadership.

“It’s always too little too late or someone else’s fault with this bloke. He’s a nasty, superficial bully. A cunning politician, but not a leader.”

A federal election is due by May 21.