National's leader is blasting a delay in the review of Karel Sroubek's case.

Immigration New Zealand has given Karel Sroubek's lawyers time to respond to its investigation.

The department ordered a review of Sroubek's residency case two weeks ago, after contradictory information came to light.

It was expected to be completed within three weeks.

National Leader Simon Bridges says the extension for Sroubek's response means there is no way the review will be done in time.

"This delay is just another sign of incompetence from this Government."