Gst registration by ddo.

Dear Members, In a State government office with a very small establishment, the bills on supply of goods and services etc never crosses the limit of Rs 2.5 Lakh.Most bills are of very small amounts,say within Rs 10000.In this situation does the DDO needs to be registered as TDS deductor under GST?If yes,what will be his scope of action as he doesn't need to deduct TDS,and what will be his liability to file returns?Has the government fixed any time frame for compulsory registration of relevant DDOs as TDS deductor under GST?