The present invention provides a data processing apparatus and method for performing aligned access operations. The data processing apparatus comprises a register data store having a plurality of registers operable to store data elements, and a processor operable to perform a data processing operation on one or more data elements accessed in at least one of the registers. Further, access logic is provided which is operable in response to an access instruction to perform an access operation in order to move a number of data elements between specified registers and a portion of a memory, the portion having a start address specified by the access instruction. Further, the access instruction has an alignment specifier associated therewith which is settable either to a first value or one of a plurality of second values. The first value indicates that the start address is to be treated as byte aligned, and each of the second values indicates a different predetermined alignment that the start address is to be treated as conforming to. The access logic is then operable to adapt the access operation in dependence on the value of alignment specifier. This provides significantly improved flexibility in the performance of access operations.