Green’s Dictionary of Slang

easy as pushing shit uphill (with a pointed stick) adj.

also ...with a rubber fork, …carrying a kerosene tin full of cowshit uphill on your head, ...hooking an eel with a blunt pin, ...shoving a pound of butter up a cow’s bum (with a size five knitting needle on a hot day)

(N.Z.) not very easy, difficult and unpleasant.

[NZ]McGill Reed Dict. of N.Z. Sl. 72: easy as carrying a kerosene tin full of cowshit uphill on your head. Not easy. easy as hooking an eel with a blunt pin Definitely not easy. easy as pushing shit uphill with a pointed stick/a rubber fork Pretty difficult. ANZ. easy as shoving a pound of butter up a cow’s bum with a size 5 knitting needle on a hot day Extremely difficult. like pushing butter uphill with a hot needle Not easy. like pushing shit uphill with the end of your nose Not easy and not pleasant.
G. Zimmatore Genetic Meltdown 162: By midday they were huffing and puffing and were completely knackered. ‘This is like pushing shit uphill with a pointed stick’.
T. Reilly Inequity 194: If this guy cries wolf and runs to his lawyer screaming police harassment, we’re pushing shit uphill without a barrow.
S. Everingham Madam Lash 280: ‘Oh, God, this’ll be pushing shit uphill in a tiny wheelbarrow,’ was his first thought.