National Party leader Simon Bridges is calling for the Prime Minister to "come clean" after Jacinda Ardern gave different timelines for a crucial phone call telling ministers that the so-called hack of Budget 2019 was not a hack after all.

And he has confirmed he won't be going to Treasury boss Gabriel Makhlouf's farewell this week in the Beehive, because it would be inappropriate to be "eating the canapes" after calling for his resignation.

The phone call, from Government Communications Security Bureau boss Andrew Hampton to GCSB Minister Andrew Little, was made on the evening of May 28, the day