"We will be considering our representation in light of our ongoing discussions with Russia, and our concerns about their activity. We don't have plans for the Prime Minister to attend, and I'm sure we will set out who will represent the government in due course," the spokesperson said.
Moscow issued invitations to numerous world leaders, inviting them to attend the parade commemorating the 70th anniversary of Nazi Germany's surrender.
The leaders of Poland, Lithuania, Latvia, Estonia and the United States also declined the invitation, while heads of more than 20 other countries have confirmed their intent to visit Moscow for the celebrations.
Relations between the West and Russia have deteriorated over the past year amid the Ukraine crisis. Numerous states have accused Russia of providing military help to militias in Ukraine's southeast. Russia has repeatedly denied involvement in what it considers to be Ukraine's internal crisis.