Yes - because a declaration of war is an act of parliament.
As noted in the Statute of Westminster (1931):
And whereas it is in accord with the established constitutional position that no law hereafter made by the Parliament of the United Kingdom shall extend to any of the said Dominions as part of the law of that Dominion otherwise than at the request and with the
consent of that Dominion:
And whereas it is necessary for the ratifying, confirming and establishing of certain of the said declarations and resolutions of the said Conferences that a law be made and enacted in due form by authority of the Parliament of the United Kingdom:
3. It is hereby declared and enacted that the Parliament of a Dominion has full power to make laws having extra-territorial operation.
4. No Act of Parliament of the United Kingdom passed after the commencement of this Act shall extend, or be deemed to extend, to a Dominion as part of the law of that Dominion, unless it is expressly declared in that Act that that Dominion has requested, and consented to, the enactment thereof.
(1) None of the following sections of this Act, ... shall extend to a Dominion to which this section applies as part of the law of that Dominion unless that section is adopted by the Parliament of the Dominion, and any Act of that Parliament adopting any section of this Act may provide that the adoption shall have effect either from the commencement of this Act or from such later date as is specified in the adopting Act.
Section 3 above, granting authority to enact "laws having extra-territorial operation", is the explicit authority to have a foreign policy distinct from that of the United Kingdom - including enacting declarations of war.
So in short, as a consequence of the Statute of Westminster - subsequent to the adoption by each Commonwealth nation as noted in section 10.1, which only occurred for Australia in 1942 - no act of the Parliament of the United Kingdom (which per force include any and all declarations of war) "shall extend to any of the said Dominions as part of the law of that Dominion otherwise than at the request and with the consent of that Dominion".
Hence, as noted in the Australian Statue of Westminster Adoption Act (1942), the Australian Parliament expressly stated its acceptance (already de facto) and consent to the United Kingdom Declaration of War on Nazi Germany in September 1939.
This answer to the question "When did Australia declare war on Germany in WWII" provides additional background.