Sometimes my bank calls me on the phone to verify a transaction before it is allowed.

The problem is that sometimes when I'm travelling, the bank can't reach me, unless I roam my phone. Roaming charges can get very expensive.

Are there banks with online banking that will do verification by email instead of by phone?

email verification is not secure, don't even think of it.

I'm not here to argue about merits and demerits.
Please help with the answer to my question if you know.
If the answer is that no banks do verification by email, that's fine too. I just want to know.
Thank you.