'Hectic task' is correct and usable in written English. You can use it when referring to a situation or task which is very difficult or time-consuming. For example, "The deadline for this project was two weeks, but the hectic task made it feel like an impossible challenge.".
This might be a very hectic task, especially for a person with no informatics background.
Business trips can be hectic enough without the added task of finding chic places to stay and eat.
Sometimes this is a difficult task in our hectic lives, but it is not impossible.
But the last day before landing is expected to be particularly hectic, with the four performing tasks usually divided among six or seven.
Between all of the diaper changes and conference calls; soccer practice and meetings, the day can be quite hectic and loaded with menial tasks.
They keep me on task and make a hectic lifestyle a lot easier to handle.
When it got too hectic a top banker weeded out the task list.
Being a terminologist, I care about word choice. Ludwig simply helps me pick the best words for any translation. Five stars!
Maria Pia Montoro
Terminologist and Q/A Analyst @ Translation Centre for the Bodies of the European Union