Is there an offline mode in Monster Hunter PS2?

I know the online servers are down so unless MH has a single player campaign it would be pointless to purchase it

I don't know as the game was not released in my country.

I assume you mean Monster Hunter 2 for PS2, in which case there is indeed an offline mode. I don't know how much depth there is to it, but it's long enough that people have written massive walkthroughs about it and its seemingly many quests.