I currently hold a Non-O (child dependent) visa and have just got a work permit and I need some advice about the additional documents that are needed to support using a work permit and source of 40k income (instead of the usual 400k in the bank)

Proof of the 40k baht income by way of tax payment receipts.

Some offices may also want copies of company registration and/or a letter from your employer. Best to contact the local immigration office to find out their requirements.

I would recommend you don’t use your work permit/job as the basis for your permission to stay (your post implies you might be). Just use the income from your job to meet the 40K pm financial requirement for permission to stay based on your parenthood.

Thanks to both you and Joe for your replies. I have a couple of questions based on what Elviajero said. Firstly, why don't you recommend using work permit and job as a basis for permission to stay? 

Secondly, if, as you said, I can just use the income from my job to meet the 40K pm financial requirement for permission to stay, then do you know what the exact requirements are for doing it this way? 

By the way, my local immigration is Nontaburi, as the requirements seem to vary between provinces.  

5 minutes ago, Daddylonglegs said:

Thanks to both you and Joe for your replies. I have a couple of questions based on what Elviajero said. Firstly, why don't you recommend using work permit and job as a basis for permission to stay? 

He was actually saying the same thing I did.

You will be using your income from working to apply for the extension of stay based upon being the parent of a Thai. He may of though you were asking about applying for an extension of stay based upon working.

8 minutes ago, Daddylonglegs said:

By the way, my local immigration is Nontaburi, as the requirements seem to vary between provinces. 

You need to ask them what they require when using your income from working to apply for the extension.

Thanks a lot - I'll pay them a visit and post on here what I find out