For a very long time the majority of immigration to Sweden was from nearby Scandinavian countries. There is a lot of people moving between the borders simply because they got family on both sides, or get a job opportunity that happens to be on one side of a line on a map and well within driving distance.

People in Sweden however don't generally think of those people as immigrants, and their social economic status is average or maybe even a bit higher than average. Sweden also has about equal amount of swedes doing the same so the end result on the haves and the have-nots is basically static for that form of immigration.

Naturally, when people discuss immigration and immigration politics, immigration and emigration between Scandinavian countries are not part of the discussion and are generally exempted through specific treaties between the countries.

In New Zealand a lot of immigrants get residency via the skilled migrant category. They are generally well educated, well informed, and often reasonable well off. The skilled migrant category chooses those attributes, including a category if you are just wealthy enough! Current scoring system I think: https://rnz-ressh.cloudinary.com/image/upload/s--mt6iKVzS--/...

Also due to the number of applicants, I believe there is definitely a filter for the more capable immigrants. They might be poor, but they work hard and usually show us locals up (at least that is what I have seen). Many immigrants might not integrate well, but their kids are usually totally kiwi New Zealanders.

The same thing occurs for tradies going from NZ to the UK: it tends to be the focused hard working and highly skilled that emigrate from New Zealand.