0T tax code for 2015-2016 but not a new worker

I'm waiting to hear back from my employer but would appreciate any advice in the meantime.

I received a PAYE coding notice from HMRC this morning that my new tax code for 2015-2016 will be 0T with a personal allowance of 0. The explanation for this is that it occurs for new workers when HMRC do not have sufficient information to generate a tax code however there has been no change in my employment. I am a temp worker employed through an agency and paid weekly but I've been working at the same company in the same role for almost nine years.

Is there any other reason I'd be assigned a 0T tax code?

Thanks,
John