Sir,
According to rule 2 (d) (B) of Service Tax Rules, 1994,-
“person liable for paying service tax”, -
in relation to service provided or agreed to be provided by a goods transport agency in respect of transportation of goods by road, where the person liable to pay freight is,-
(I) any factory registered under or governed by the Factories Act, 1948 (63 of 1948);
(II) any society registered under the Societies Registration Act, 1860 (21 of 1860) or under any other law for the time being in force in any part of India;
(III) any co-operative society established by or under any law;
(IV) any dealer of excisable goods, who is registered under the Central Excise Act, 1944 (1 of 1944) or the rules made thereunder;
(V) any body corporate established, by or under any law; or
(VI) any partnership firm whether registered or not under any law including association of persons;
any person who pays or is liable to pay freight either himself or through his agent for the transportation of such goods by road in a goods carriage:
Therefore only in case of proprietary firms, association of persons , the service provider, that is, GTA is liable to pay service tax. In all other cases the service tax is payable by the person who pays the freight.