He phoned Dr Haines shortly after 5pm on Wednesday to commend her on winning the contest for Indi as part of the federal election which saw the Coalition re-elected on Saturday.

"I rang up Helen to congratulate her on her fantastic campaign and wish her well in her new role," Mr Martin said.

The father of four delayed conceding until Wednesday in the hope postal votes still being counted would bridge the gap between himself and Dr Haines.

Mr Martin estimated those ballots needed to be running two-thirds in his favour, but given they were only 53 per cent he could not see a way to win.

As of Wednesday night with 3540 postal votes still to be processed, Dr Haines was leading Mr Martin by 2501 votes on a two-candidate preferred basis with 51.39 per cent of the vote to 48.61.

Dr Haines welcomed Mr Martin's concession as the second last step, behind the poll's declaration, to her becoming North East Victoria's federal representative.

"I congratulated him and his team on all their hard work and passed on my best wishes, not only to him but his family, because it's a big undertaking," she said.

Dr Haines expects the poll to be declared in the first week of June with valid postal votes able to be received and counted until May 31.

She is yet to speak to parliamentary officials about how many staff she will have, but will maintain Wodonga and Wangaratta offices.

Predecessor Cathy McGowan was allocated two extra staff for her second term after Prime Minister Malcolm Turnbull found himself in minority government and reliant on her support from the crossbench.

Mr Martin said he knew from Saturday evening as votes began to be counted that it would be tough to win Indi.

"I realised that on the night we were in a very difficult position and I was very disappointed in that, with the Morrison government getting back in," he said.

"A lot of people would have thought that neither Helen or I would have been in government given the polls, but given the Morrison government got back we've missed a great opportunity to have the seat of Indi in government."

Mr Martin was non-committal when asked if he would stand again for Liberal preselection.

"I'm not ruling anything in or out," he said.

"It's time to spend time with the family and work out what's next."

IN OTHER NEWS:

Mr Martin said he expected there would be a number of reviews by the Liberal Party into the Indi result and he would be keen to contribute his thoughts.

The party attracted a 7.50 per cent swing to it on first preferences and a 4.13 per cent two-candidate preferred swing, compared to the 2016 election where Sophie Mirabella stood for the Liberals.

Meanwhile, vote counting at the Australian Electoral Commission's office in Wangaratta was slowed on Wednesday after a letter-opening machine broke down.

The failure meant hundreds of votes were opened by hand before being scrutinised.

A replacement machine is due to arrive from Melbourne on Thursday and be in service after midday.