The packet of biscuits has passed its expiry date or The packet of biscuits has past its expiry date.

Or both sentences correct?

1 answer

No.

The first is almost correct. The correct verb is "passed" but there is no such word as "expiry"!! Use "expiration" instead.

The word "past" can be used as a noun, an adjective, an adverb, or a preposition -- but not a verb!