The Defence Minister, Christopher Pyne and the Defence Industry Minister Steve Ciobo, both cabinet members, are set to announce they are quitting parliament at the election, in the latest of multiple high profile exits from the Morrison government.

These foreshadowed departures – in this case within the same portfolio area - open the government further to Labor’s criticism of being a lame duck administration.

Cabinet ministers Kelly O'Dwyer and Nigel Scullion, junior minister Michael Keenan, and former deputy leader and foreign minister Julie Bishop have earlier announced they are leaving at the May election.

Pyne, 51, Leader of the House and a moderate within the Liberal Party, has been in parliament since 1993 and is an active factional player. He holds the South Australian seat of Sturt which is on a margin of 5.4% Pyne only reached his long held ambition of becoming defence minister in the reshuffle after the removal of Malcolm Turnbull.

Ciobo, 44, holds the Queensland seat of Moncrieff and has been in parliament since 2001. His seat is on a safe margin of 14.6%.

Ciobo was demoted in the Morrison reshuffle last year, losing the trade job although remaining in cabinet.

Scott Morrison, in North Queensland to announce a relief package for farmers and graziers after the devastating floods, batted away questions about the expected announcements. The government had hoped to push the story into the dead Saturday news time but it leaked out.

Both ministers have been fending off questions about their futures. On the show they share on Sky on Friday, Labor’s Richard Marles asked Pyne about whether he was resigning.

Pyne told Marles: “Once I decide to announce my retirement you will be the first to know”.

Marles said Pyne had had a stellar career and if it were true that he was going, “I for one will miss you”.