The changed political dynamic in Parliament may affect coming moves regarding the country's intelligence agencies.

National's lost one vote in Parliament as result of the Northland by-election result.

The result comes as the Government's due to review the SIS and GCSB this year

United Future leader Peter Dunne thinks he will have extra leverage with the Government as a result of the by-election.

He says the review will have to lead to more robust legislative oversight.

"I've indicated some real concerns that I expect to see addressed and that won't change."