The Conservatives have called for the Ministry of Justice to explain why it failed to publish figures detailing how many prisoners have been released early.

Shadow justice secretary Nick Herbert used a point of order in the Commons on Wednesday to raise concerns over the MoJ's failure to release data as expected.

The statistics would have shown that more than 4,000 violent prisoners and almost 25,000 prisoners had "been released early onto our streets", he said.

Herbert pointed out that the department published "every set of data scheduled to be released - except the early release figures".

"Will you invite the justice secretary to reassure the house that these figures will be published immediately and that this was not a shabby attempt to bury bad news on the eve of the local elections," he said.

But Commons Speaker Michael Martin said he would not be inviting justice secretary Jack Straw to make a statement on the issue.

"It is up to ministers what they publish. It is not up to the chair," he said.

"It may be a point he wants to raise with the minister but it's not a point of order and I will not allow the matter to continue."